I think I might have found it:
http://www.travla.com/business/index...roller=product
it supports flex ATX PSUs that can go up to 400W (but I won't need that), a 3.5" drive, a slim optical, and looks like I can squeeze a 2.5" drive into it without affecting ventilation.
it had ok venting (
compared to some other cases), so with the Phanteks heat sink it should handle an i7 fine (problably not overcloocked though).
I'm a little disapointed I can't find a similar case that supports GPUs but this should do (ironically they have one, but it relies on picoPSUs that only go to 120W) Intel HD 4000 is OK for HTPC use but I hope Intel doesn't take too long to offer GT3 in the high-end Haswell desktops, as they are supposed to be comparable to a Nvidia GT 650m (on mobile chips - desktop version may be better because power constraints aren't as severe)
I did figure out why I've never seen a case like my preferred design: It has a potentially fatal flaw. You cannot put anything on top of the case that would obstruct ventilation. To be honest I consider it fairly unlikely that something would be put on top of this case, especially because it will be tucked into a A?V cabinet. But it can happen.