The entire Alternate Project started with the 260 Idea Book. The whole project started with the small Futuron rover whown on the first space page. I had wanted to build that for years, but it wasn't until recently that I figured out how. Then I realized that with the resources on the internet, I could figure out how to build the alternates for many other Lego sets, and it all went from there. :)
260-1: Surface Transport The first alternate I made instructions for.
260-2: Surface Transport
Disclaimer: These are not MOCs. I didn't create them. What I did was take a picture of the alternate and a list of parts for that set and figure out how it was built. The instructions for the models, however, are created by me.