The shameful thing is, its piss easy to get working. I got it working on an old Humax freeview box a while back, the controller mapping via a javascript inject file is all that has to be done, and even then all you're doing is mapping up,down, left, right to their keyboard counterparts, and 'menu' to 'backspace' and then 'play' to 'enter'.
It's sad how simple it is, its already h.245 compatible, the iPlayer streams are the exact resolution needed, and there is no flash to get in the way of things as the BBC already made it fully compatible with any set top box running a very simple browser.