5-Speeds? Strong Enough?

Well, my original plan was to start out with a mild 450hp 408ci BB. But my plans have changed and I am looking into a twin turbo setup on something like a LS2 or LS1 (maybe a BB??). It will have probably about 700-1000hp/tq.

Is there any overdrive 5-speed (or 6) that will handle this kind of power? Originally I was planning on a TKO600 for the first option, but I've realized that it will not handle the new plan?? This will be for street driving and the occasional strip..

Thanks,
Todd