I'm in Rocklin and have the mello-roos plague as well. Luckily mine expires in 2012. Mark is spot on for the time frame. Mello-Roos is actually the developer not wanting to pay for street lights, schools, roads, etc. and the City not wanting to pay either, hence forcing them upon the homeowners.
They are in place for 40 years :-) No Joke. But the average price per square foot is cheaper there than in other places so your overall payment ends up being a wash. There aren't a lot of places around here where you can get a 3,000+sqft home FULLY loaded and upgraded for under $400k. I guess paying the mello-roos is the price you have to pay for such a good deal.