In my opinion, Integra is a control freak, dominant and has a very masculine persona. She smokes a cigar and has a nice gun. I don't imagine she paints her toenails pink and wears frilly undies beneath her suits. She knows what she has to do and more than that, she LIKES destroying vampires and freaks and ghouls. She enjoys defeating her enemies and having the glory of Hellsing built up in the eyes of God etc.
There are only THREE instances of her crying and only one of them is cross manga/anime. And one of them in the anime takes place while she's unconcious. And the other when she is thirteen. The gravity of the situation that would make her cry would have to be earth shattering.
And I don't see Alucard would comfort Integra. Why? Because he exploits each of her weaknesses in order to make her stronger. He does this with Seras too, but more so because she has so many weaknesses. Alucard respects her strength, her force of will and her unflinching ability to order the massacre of humans simply because they unwittingly support the enemy. The woman has a spine of steel and is not soft and mushy underneath. She's a fanatic. In my opinion, seeing her cry over a broken nail or something incredibly trivial and having Alucard comfort her is like George Bush hugging Saddam Hussein. It ain't happening.
But Integra cried when her troupes died and she had to put them down as ghouls. . I see the invasion of Hellsing is almost an act of rape upon her. Hellsing is her pride, her honor, her heritage and the future glory she will give it. The Valentine brothers took all that away by forcibly invading. And on further insult, she had to destroy the men that were turned against her. She mourns them because they were the guardians of the organization itself. In war there has to be sacrfices and she understands that, but war was thrust upon her and thus was a shock. But I digress.
I don't really think, Alucard would give Integra flowers or candy. If he gave her jewelry, I think it would be something highly personal between them, and a mark of his on her. A peice of obsessive possession. And it wouldn't be flowery or obnoxious. Likewise, if Integra gave Alucard anything, I think it would be her blood. Lets face it people, she's not going to pick up a Cosmo and read "Fifty ways to please your man" *interesting article btw*. On that note, she's a virgin who has probably never been kissed. I don't see her giving an expert kiss or having perfect sex the first time out.
Besides that, any sex they have, any fooling around they have will be based on primitive lust, roughness, blood and dominance. But then that might just be my bdsm preference showing

As you've noticed, I've used dominance as a recurring theme. It is. If they are both so uber dominant how can this work? Because Alucard would never go for someone who wasn't of their own mind and possessing their own will to control. And Integra would eat alive any man who catered to her will. They need the dynamic because it will never grow old, the battle of wills between them. That, and each of them give a bit of ground in their own way. It's just the coming about of how and what ground they give that perplexes and can make or break a storyline.
OOCness. No story is going to be without this because we're not Hirano but I think an effort to stay true to charactor, as seen in MANY good ones like Feel Lucky on FF.net, can be the same thing. I think language really helps in this aspect. Language as well as the selection of words. I don't see Alucard secretly wish to become good or human, and is damn sexy as a gun toting badass. Integra, in my opinion, does not secretly wish people see her as feminine. On that note, I would think she probably finds being female a chore all together and one night of rough and bloody sex with her vampire is not going to change that.
And I don't know if this has been brought up before but I see the HUGE similarity between Vladimir Tepes and Integral Hellsing. Both held honor and duty and Church sacred. Vlad fought off a freaking LEGION of Turks to keep out Islam. Integra faces a LEGION of freaks and vampires. They both put pride and duty ahead of everything. Vlad married a king's daughter just to get his ass out of jail and get help to kick out the Turk's. Integra assumed a masculine role and has little to no contact with the outside world except in a necessary capacity.
Both have suffered their own personal losses. Vlad's first wife killed herself when he was away and his castle was surrounded by Turks so that they couldn't use her as a bargaining chip. Integra has lost her father, killed her own brother and buried a score of troops.
Alucard despised his brother who became a bitch of the Turks leader. In the anime version, both were betrayed by those they fought for in the end. But most importantly, both would use any method necessary to win. Consider that for your vampire!Integra fic if you need a way to get her to submit and can't really think of a plausible one. Above death, above her humanity I think she would put her victory. Some might disagree, but I think she is obsessed enough to order a massacre knowing it is more on her hands than on Alucard's.
The similarities between them, the pridefull arrogance of Tepes before his betrayal, before his fall, and the way Integra is heading could work for vampire fics of her. But it also works for AxI.
Also, I think that Alucard is her one ally. Walter may be her irreplacable steward, but even he will betray her one day by dying. Alucard won't. Alucard is assuredly loyal to her by the seals and because he has fun killing things. Though there seems to be other factors involved in his service to Hellsing that will hopefully be explained later. Such as the Queen and how he was sealed and things like that.
But yeah. This was my little diatribe because I just got done cringing at a few things in the pit of voles and am also trying to convince Thess that a little smut AxI wouldn't be too inappropriate cannon wise. Especially if she found some unique way of doing it. *Gleam*
Just a note this is my opinion and take of the situation. Sorry if it's a bit of a lecture I'm a creative writing TA and am used to the Lecturing At Sleeping Freshmen and Being Quite Anal format, this also WAS NOT inspired by anything I read on here. My only complaint about the forum is that it's not got as much fiction or art as most of us wish it would. Oh, and it took me about five times before I discovered that little exlamation button wasn't the edit button. Heh heh. . whoops. . *sweatdrop*
So anyway, just to review A) Not bitching at anyone here. B) Stating my opinion as to what good AxI would entail and C) Want to know what OTHER people's opinion's of good AxI entails. And D) Convincing Thess that really, a relationship, however dysfunctional, could work between the two. And if anyone is still offended, realize that I also wrote this in explination of my own fanfiction that I'm working on and trying very hard to keep in charactor because I realize how badly I want to the two of them to get it on.