On the 777 (this was the -200LR demonstrator) the overhead rest area is pretty snug but has room to comforably move about. They have set it up the bunks so your head is "down the tunnel" I'm not so sure about that but they are also angled to be pretty level when in cruise ( in other words on the ground they are 5 deg 'feet down'.
Last week I was in Seattle with a bunch of others getting the everything you want to know about the 787 speil and was told that its crew rest will be basically the same as the one fitted to the 777s.
BTW the Flight Deck on the 787 has got loads of cool stuff incl dual HUDs, EFBs and a moving map that goes from .05 nm (with airport layout to 1280 nm. Oh yeah as well as the when will you be at the selected height,alt of FL at present ROD or ROC it'll have one that will do the same kind of thing for speed el nifto!