Would it be possible to give all your information to your Californian friend and have him register it under your name at time of purchase (if that's possible or even legal)?

(edit) Now that I think about it, technically, it's black marketing the software. I lived in Germany for 4 years and had all sorts of dire warnings about buying things in the US for German friends without paying the tax. However, I do believe it would have to be in large quantities before any official would get their knickers in a twist.