Well, the HP 1055s are pretty decent machines and I would think you'd be happy with the results if you printed your graphics on them. The paper really makes all the difference in the world so I'd suggest printing samples on several types of media and using several different settings - using the "coated paper" setting is not always the best choice when using coated paper, go figure

I don't have photos that do the graphics justice yet but here's a small section:

The CP is covered with 1/8" plexi and the image is compressed - both of these conditions contribute to a poor representation of the print quality.
All I can say is that I really can't imagine it looking much better than it does - I'm very happy with the result. My source image was created at 200 ppi - plenty of pixels for inkjet output. I added a little texture to the background so it is not straight black (matches the cab quite well, I think). I also applied a few coats of a clear acrylic spray to protect the CP image a bit.
The marquee printed on the same media works great sandwiched between two pieces of plexi and with a flourescent backlight. I experimented with various types of media including vellum and this Azon APB provided a much nicer result.
If you know someone that has one of these Epsons or a similar printer, have them print you out some samples; otherwise, if you send me some graphics I'd be happy to print and ship you a small sample at cost.