I currently have a Mega2560 with the LCD4884 Shield. The Shield is good for putting out text and simple pixel images. But I am wondering if there is something that has a full range of colours that would work with the Arduino? The screen size would only have to be a few inches in size.
There are actually several shields that have color screens on them. Many of the shields are just regular mini TFT displays, however there are also touch screen ones.
Here is one from Adafruit that includes a MicroSD holder and a Joystick.
Here is one from Radio Shack that features a 2.8 inch screen with touch capabilities
As far as screen size, many of the screens are only about an 1 inch across, however the biggest I have ever been able to find are 2.8 in.
It's a 1.77" screen, with a resolution of 160x128. It has a micro-SD slot in it, which is easily accessible. It is a color screen, with up to 18 bit per pixel.
The extremely nice thing with this screen is that since it's officially supported, you don't need to do anything extra to support it. The official Arduino TFT library works perfectly with it. However, according to Jameco:
Library Update: There is a known issue with the TFT library supplied in IDE versions 1.0.5 and 1.5.4 Beta. You will need to replace the library. We have zipped up the updated TFT library for both versions available here. Just delete the existing library and copy in the replacement for the appropriate IDE version and restart the IDE. (IDE v1.0.5 or v1.5.4)
So beside that minor fix, everything should be easy and quick to work with. This page has some code samples which should make it easy to work with.