There is a very nice Trex 600 conversion kit from HWC coming out within the next few weeks at Century Heli. http://www.centuryheli.com/products/...¤tid=844
. Its really well engineered and comes complete with a gasser clutch and cooling fan system. I'm going to get one to convert my Nitro Pro.
If you don't already have a Trex 600 Nitro I'm not sure its cost effective though.
At which point I would like to add another vote for the Century Radikal G20. I like mine as well.
In either case, if your an ultimate 3D god, neither gasser solution will satisfy you. You can 3D them but they are heavier and not as nimble. In this case your best bet to get out of nitro would be to go electric.