I would like to see a 3000 kv 60 or 70 mm medusa motor, just so i wouldn't need to use a 20 tooth pinion gear to get the speeds I want with 4s. The novak hv4.5 is just about right speed with a 9 tooth pinion gear, but that is too small. 12-16 tooth pinion gears seem to be about the right size - not too heavy and not oddly shaped.
Check out my custom converted 8ight:
Sub 7lb, lowest CG of any 1/8 buggy