I don't see the point of passive cooling given that the fans on the 750Ti cards are some of the quietest out there.
I would pull my hat for a mod that made the cooling of a 750 Ti a single slot solution. i.e. rip the cooler from an 8800 GT and fix it to the 750 Ti

ALSO: I really want a low profile version of 750 or 750 Ti.
Christian