I don't think the contest should be over who produces the most. That just gives the hardware to the people that need it the least. I read earlier that whoever has the greatest percent increase in their own production. That way, everyone is equal, unless you want to work out a handicap system like in golf.
Anyway, under the percent increase system, if someone goes from 2 a day to 3 a day, by finding another machine to crunch on, there's 50 percent for them. It's harder for the *orsemen to increase though. If the Norsemen are getting 1000 a week, they'd have to hit 1500 a week to get the same percentage. I think that this gives everyone a fair chance, and new members or the members that aren't addicted and buy boxen just for seti won't feel like they can't win agains 1000 a week...
**edit**
A good prize might be a memebership into the planetary society, the organization that funds seti the most.