Thanks for the compliments. I wanted to have the cab ready for a superbowl party, and didn't have time to send the artwork out to MameMarquees, so I went to local Staples. $40 for both pieces, and they came out great.
They're both printed on regular paper stock - the wide format paper is a bit thicker than regular printer paper, but it shows marquee light through ok (you can tell there's a light on, but that's about it). I wouldn't recommend it for marquee printing unless you were in a rush and wanted something quick and cheap.
The control panel came out great - it's glossy paper, which looks even better under the lexan. Staples did screw up once on the control panel (I had printed size reference marks on the document, and they still printed too small! - Measure before you leave the store.). However, they reprinted and I picked up the final product about 40 minutes later and it was perfect.
I went with a simple picture (rather than true control panel with button outlines, etc.) because I didn't really layout my control panel in software before I built it. I was concerned that my measurements would be off on any precision printing, so I printed an oversize picture where button layout wouldn't really matter.
For the side art, I bought some cheap fabric pattern transfer paper. You put the paper on whatever surface you want to transfer to, and then you just draw on the transfer paper. It leaves behind a white line that is not permanent, but is easily visible. I'll tape the transfer paper to the cab, print out a large picture over a bunch of 8.5x11 sheets of paper, and tape those to the transfer paper, and then trace the image. The transfer paper will leave behind a perfect picture.
I think the hardest part will be taping the picture to get nice crisp lines, but I think I can pull it off with a razor and some painter's tape.