I used a JVC 27" TV (JVC AV-27530) in a cabinet that only had 25-1/8" clearance inside. The TV is actually 25-3/4" wide or something, but the case will flex and fit into the cabinet if you modify it like I did in the link below:
http://forum.arcadecontrols.com/index.php?topic=54556.msg534947#msg534947I did have to decase to mod it, but I put it back on, then shoved the whole thing in the cabinet. So technically it is not decased... Works great!!!
These TV's are close to $200 new, plus they have Component inputs, which is what I am using, and it looks awesome!!!
You could probably get a 27" JVC TV with the same form factor but with out component inputs from Craigslist for $50 - $100

I have a Sharp 27" TV without component video which might also work.
Basically any 27" TV that does not have the speakers on the sides would theoretically work if you mod the case.
Or you could try to find a 25" TV, which might be a little skinnier...or 24"...or maybe even a 23" from Sam's Club:
http://www.samsclub.com/shopping/navigate.do?catg=535&item=170360&prDeTab=2&pCatg=5878#AGood luck.
