1. thanks you guys
2. any chanceof me beinga guest riffer in the future
3. I'm going to be without the internet for a while. plus the computer I'm on doesn't have spell check.
Well the guest riffing thing was the result of a contest. The community of Iriffers was narrowed down to a top 10, I think from some scoring system or decision making process the guys at Rifftrax used. I don't really have the data to make an educated guess, but I think bacon was involved. Then a winner was chosen based on some combination of user votes and sales of the riff. The winner was Doug Walker from Thatguywiththeglasses.com, who already boasted a pretty hefty Internet following (his website is his full time job).
I should also point out that with the contest, Doug and his cohorts were doing the riffing. Mike, Kevin, and Bill were not present on the track, except in the introduction, and their role was mostly advisory.
If they do another contest, I presume Doug will be disqualified from winning again. However, there are several professional grade, established riffers out there who you'd have to compete with.
I'm not trying to be a dick and rain on your parade and tell you "give up, you'll never succeed". Just that the process for collaborating with Mike and company is a little more formal than you seem to think it is.