If you use the mechanical breaks, then there are a number of boat or plane escs that will work fine, say upto 12s & 120-200amps as a rough specification. Some of the large flat escs on hobbycity.com would be good, or if you wanted a better 'branded' esc, then the Castlecreations ICE escs would be excellent- depends on your budget really. The 22xx motors should be plenty big enough, they are comparable to Neus 22xx series I believe, so something that can produce 2000watts of power or more (peak/ maximum) should do the trick nicely.
I have no personal experience, btu there are a fair few 1/5 conversions around, take a look and see if any of the info is of any use to you:
http://www.rc-monster.com/forum/showthread.php?t=23762 1/5 onroad
http://www.rc-monster.com/forum/showthread.php?t=21657 1/5 MT
http://www.rc-monster.com/forum/showthread.php?t=23529 1/5 MT
http://www.rc-monster.com/forum/showthread.php?t=24159 possible esc?
http://www.rc-monster.com/forum/showthread.php?t=9298 1/8 think-tank, might be useful
http://www.rc-monster.com/forum/showthread.php?t=21406 lehner motor discussion
http://www.rc-monster.com/forum/showthread.php?t=19317 1/5 onroad
http://www.rc-monster.com/forum/showthread.php?t=8236 1/5 onroad
http://www.rc-monster.com/forum/showthread.php?t=18221 1/5 FG Baja
http://www.rc-monster.com/forum/showthread.php?t=24325 homemade 1/5
Hopefully there will be something useful in there- thats most of the useful threads so far as I can see.
