Hmm...perhaps even Capcom doesn't know what to do with him yet..hhehehe
Maybe is is one of those analyzing robots from the Street Fighter animated movie...bah
Anyways here is some scoop from the SF Plot / Canon guide:
Like the majority of SF3 characters, Capcom didn't make an official bio for Q. This would be the one case where they could make an excuse and say they didn't make a bio for him on purpose.
Street Fighter 3 Third Strike: Q is... basically just wandering around or something. Really not much, here [based off in-game storyline. Or... more accurately, the lack, thereof].
Where Is He Now: Probably being pursued by the C.I.A. [Official]
Miscellaneous Facts and Notes
What is Q? He makes clanking noises when you hit him and he doesn't have a skeleton when he's electrified. Hmm... it's stated that he is in fact a certified living person and thus not a robot, though. His gender is unknown, even (so I'm just referring to him as 'he' for convenience sake). A cyborg, maybe?
He is known in the C.I.A. as 'the man with the trenchcoat.'
It is said that he has a connection with Remy, though this connection was never stated (Hmm...? There's only one missing hole I can think of for Remy right now... *cough*)
Q 'witnessed the downfall of Shadaloo'. Exactly what this means, no one knows. After that, he's been spotted in a lot of different parts of the world, mostly in Street Fighter tournament arenas...
His name, Q, supposedly was chosen by Capcom because Q is the first letter of Question, which goes with how there are tons of unanswered questions for Q and very little official information on him at all (which is done on purpose for some wierd reason. Guess Capcom wants a wild card character in reserve or something). Note that this doesn't mean that Q stands for Question in the storyline, though.
Q is a rip off of Tekkaman from the manga, Babil Nisei.
Q is Balrog in disguise. As seen in Balrog's SF2 Revival ending, Balrog caused the downfall of Shadaloo. Witnessing this, and worried that now his ass is grass, he takes on a new identity and becomes Q! This is why Q has a dashing punch like Balrog does, and why the C.I.A. is after him and also why he fights with no dexterity whatsoever!!!! Just kidding. Or... at least, I hope I am.