www.makemkv.com

How can I stream full Blu-ray rips from a little NAS/media server, to my TV? preferably without having to buy a set-top box, but honestly at this point, whatever works.

It needs to support FLAC (or PCM, it's converted cousin) and full bitrate blu-rays.

you could always build a client pc to go under the tv and then use media portal to play the bluray mkvs or flac files etc, if you put a tv in another room and another client pc you can stop the movie in one room and resume playback in another.
http://www.team-mediaportal.com