if you're gonna be this picky about it then you're gonna have a really hard time finding one...
i spent a long time searching for aluminum track frames and really only found a couple that were worth a ****... the one i ended up getting i've yet to see anywhere else, and have had a hell of a time just getting any information about it...
also, the chainstays on most almuinum frames i've dealt with will bend easily and stress-free enough to put a narrower hub in the back... never touched an iro tho, so i can say for thems...