Hi Happygeek,
I've been chasing the same thing a lot of ways. Check out my thread in Mods and Maps here:
http://forum.shrapnelgames.com//showthread.php?t=44008
Lot's of the veterans have chimed in with great suggestions. Map commands and the RanDom and SemiRandom utilities by Ballbarian are great to pump up the SP challenge.
Cheers,
Maer