Yes, and Aqua, Collatz, DNETC, Cosmology (there the TeAm needs help), Quantum Fire Alpha, Einstein, MalariaControl, WorldCommunityGrid (that is one group of projects and a site which almost never is down or out of WUs) ... plenty of worthy projects that are great as backups.
Set seti@home to a resource share of 1000 and the other projetcs to 10 or 50 - as soon as seti is up their WUs get crunched. If you have enough seti-WUs, abort (not reset or detach) the other WUs / project and Seti will be crunched allone. When Seti is down the other projects come in again ...