Most receivers today do. Its trying to find out if there is any alteration going on that is more difficult to find.
For instance, I just learned today that my 805 elevates black levels when using 24p. Sharpness/detail is fine, but video levels are shifted from 16-233 to PC levels 0-255. Others like 1080/60p, 1080i, and 720 are fine. 806 actually suffers more than 805, but I can't recall exactly how.
I would guess that Denon would be very good about this, but OTOH I read that a slightly older model couldn't pass 24fps, but IIRC it was an entry model. Good luck on your hunt.
Oh Yamaha 663 clips BTB/WTW for HTPC users, but funnily enough, I believe the 661 is fine in this regard.
-jostenmeat