I purchased a little 2.5" screen on hmmBay this week with the intention of using it in a PCE GT.
Have to say it looks very suitable and will keep the unit looking very stock. Price ~$60.
The innards of the little screen are very small, will easily fit within the PCE GT.
Hoped to be able to determine the pins on the ICs and maybe bypass composite and pipe in S-Video or RGB, but as is the case with a lot of this no name stuff, the ICs are not easily identifiable. At this size composite is probably more than adequate.
Sorry, pics have come out yuuuuuuge!