Hey,
I've been having this problem lately where the command-<tab number> hotkey stops working after a while. Restaring iTerm resolves the issue temporarily until it occurs again. I'm pretty sure this has only been happening at work, where I may get it twice a day.
* Mac mini running OS X 10.5.8
* iTerm Build 0.9.6.20090415
Uh oh, appears to be duplicate:
https://sourceforge.net/tracker/?func=detail&aid=2834131&group_id=67789&atid=518973