I recently made up a new gear box mount out of some 4mm steel plate and 2x1 1/4 poly bushes. Its stood up to a hammering quite well i know its not the same as with an s/c but its pritty strong.
Ill get some pics up of it.
I did notice a bit more vibration from it to start with but now its barely noticable. much quicker from a standing start and a but more feedback from it.