I second Arct1k's suggestion. 5t and 6t are limited to 2s, 7t 3s with caution, 10t 4s with caution, 14t 6s. They are hard to find though, as they aren't being made anymore. I believe Mr Holmes is selling off the last of his stock now, so if you want them you'll have to be quick. Either that or keep a very close eye on the RCC classifieds. Another option though will be the team br00d axle busters. They aren't being sold yet but the wheels are in motion I believe. Plus I'm sure Eddie could have them wound to any kv you needed. They will be a standard size 540 with not so standard power

Kieren