Yes there's a Pioneer model at a nice price of $180 I believe and it has both formats, although i can't tell you how good it is. You'd use the analog inputs from the player to your receiver, yes your receiver must have 5.1 analog inputs. No your speakers don't have to go to 20 khz to enjoy it, but obviously better speakers will get you better sound and hence you would enjoy it more with better, fuller range speakers. And without a center your mains would share the signal so you won't miss anything, you'll probably have to tell the player you don't have a center channel though. I don't have any experience with either of these formats so I can't answer the rest of your questions.

-Joey