I'm just thinking out loud here but.... What if you were to mount using normal tube rings towards the bottom of the tube (where it is solid) and then all you need to do is build some sort of balancing bar to extend out the rear of the scope to balance it. Or just put a bit of wieght behind the mirror to balance. The Skywatcher truss dobs seem to have a lot more solid tube at the bottom than the Lightbridges. So maybe this method would work????
If you were using an eq6 or something larger the extra weight may not be a problem. If it was a 12" scope you'd never get away with it....
Only downside other than the extra weight would be that the tube wouldn't collapse with the rings attached.