Yes, you can make them yourself if you have the tools, and they can have rubber isolation points to all but remove the engine's 'nad rattling harmonic vibrations from the frame. I'm designing a prototype set out of steel for the new bobber frame I am producing. These will also swivel, so this way you can "clock" the engine exactly where you want it. Eventually, once the frames start selling, this motor mount design will be machined out of aluminum. Much less work for me.
'BrettMavriK