This is a little premature, but I have been working on it for a while and wanted to post a teaser up. It's covered in bondo and not very pretty, but it should give you guys an idea of the shape. The plan is to finish this positive mold, and then vacuum form black ABS over the front and back, and then fuse the two together. Inside will be a Magellan Roadmate 1700. I have the vacuum former built and the ABS is on the way, so I should have something more to show by the end of the week. It's hard to tell by the picture, but this will replace the center vents above the radio. Ignore the distortion of the iPhone, that bottom edge is straight.
Once the actual ABS enclosure is built, I will add a backup camera since the 1700 has an A/V in. Another obstacle in the horizon is how to keep the warm/cool function of the center vents, since it also controls the side vents.