I found an awesome source for cheap Arduino-compatible shields if anyone's interested.
http://www.sainsmart.com
They're a Chinese outfit. I bought their LCD touchscreen module for just $18 compared to roughly $50 for the same type of thing from Radio Shack, Make, or other companies. They offered free shipping to the US, and it arrived in about a week.
I haven't had much of a chance to play with it yet, but I'll report back once I've gotten it working. I plan to experiment with some touchscreen-based MIDI controllers using it.
