Is there a color LCD display for an arduino?
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.