Here's Aangel's 8T.
http://www.rc-monster.com/forum/showthread.php?t=6832
There should be some others around here somewhere.
I'd just use the stock spur with the hardened pinions from rc monster. Depending on how many teeth the stock spur has, a 13 or 14t pinion should be ok.
If your racing, mid 30's is a good place to start off at I think (depending on your track).
This is good for working out gearing
http://www.scriptasylum.com/rc_speed/_top_speed.html