I have been asked to make an R2D2 cake for a groom. I am not sure about this. I have looked at the great pix here and wonder how long it took people to make them (I also have to do the bride's cake, but her design is very simple and shouldn't take me too long.) I would appreciate any input.

I was just on searching for the same thing!
Here's a tutorial that may help with the actual design and construction:

http://www.bsideblog.com/2008/06/making-the-most-amazing-r2d2-c.php

Wow, that is pretty cool. Thanks for the info.