What electrics are you using? If it's brushless then I think your going to have to find a slipper. If not take a look at Luke's thread here:
http://oople.com/forums/showthread.php?t=48668&page=23
It's a really handy I keep going over bits now and then.
But if you do need a slipper robin c on here has had a couple of bosscat ones made I'm sure if you ask him he'll be able to get you one done.