One option would be an Archos 605 wifi connected via aux in in a proper stero. If you don't have one, then you can probably get by with an amplified dock. Sound quality won't be mind blowing though. I've checked and
it does say it will connect to NAS boxes.
Although if the Squeezebox will connect to NAS then its probably a better solution.
Also you might want to look into an Airport Express router thingy as that streams itunes wirelessly. Maybe you can connect your NAS through itunes on another machine and do it that way.