I have a couple of small 12v LCD screens hooked up to a console here at the Faire. Sadly, the console I brought is wonky so all I can show is the Master Title Screen. But it does show the successful use of some of these handy items which can be found.
The two in particular I have are these:
4.3" "Flip-up" screen eBay Auction -- Item Number: 381172263571
5" screen eBay Auction -- Item Number: 360698452748
These are after-market back-up camera screens for cars. They also have no sound so you will need to make provisions for external sound. Even so, there is the possibility one could be mounted on or even in the console.
During my experimentation finding these screen I also tried at least one which was a failure. This one, specifically:
3.5" LCD eBay Auction -- Item Number: 150715309597
Like a lot of composite up-scalers, some of these LCD screens are not going to be able to sync to the 240p signal output by the TI. Ones which do may actually treat the signal as 480i so there will be skipped frames. It will be a crap shoot to find one that works.
I am planning right now (and we know all about the plans of mice and men) to open these up and see what the chips used are to help locate other units which will work. I will make a blog post when I do.