If you want a case right now, I would buy the often-touted Contour Design Showcase. It doesn't meet your needs exactly, but it's the closest you can get right now.
1. The Showcase covers everything, but there are cut-outs for the controls, bottom port, and top ports.
2. The face, but not the rear of the Showcase is transparent. But as the name implies, it's a pretty good....showcase. (That was painful
3. As I said, the controls are cut out, so you can use them. If you want them protected...maybe some Pacific Design Wheel Tape? (You can get it in clear.)
It seems like what you're really looking for is something like the iSee or the Speck Flipstand. I have a 30GB photo, which has the same dimensions as the 20GB color, and I too was disappointed to find that none of the totally clear cases would work with my iPod.
When I heard about the 20GB color, the first thing I did was check the dimensions and I was ecstatic to see that they were identical to that of my iPod. I would bet a significant amount of money that future iSees, Agent18s, etc, are compatible with 0.63" iPods.The 20GB is the "standard" iPod and now that its dimensions have changed, case manufacturers will be under pressure to make their cases compatible with the new dimensions.
In summary...buy a Showcase or wait and see if the totally transparant cases are manufactured in new dimensions.