Hey its strange although I have short legs I still find that they get bent up when seated. The only thing to watch out for is less ground clearance. This is not so much of a problem if you always stay on road but off road I think you want a clean underbelly otherwise the lowered pegs may snag on things or bottom out.

I think a good thickness of aluminium plate that you could bolt in place and then fix the pegs to.

Or how about using engine bars as highway pegs so you retain the current ground clearance but could stretch out your legs on long hauls.