The skewer is not a weightbearing peice, it has enough work to do holding the wheel in place as you jam the pedal. Give it any more work to do and it will end in tears. You wont even have a decent surface for it to grip onto. No just dont do it.

M5 steel bolts can take more weight than you can carry.

Check out reynoldsusa.com for the inside info on all those numbers.

I blame the MTB magazines, with all that crap about frames being "spoilled by having threaded eyelets". You are not compelled to use them, but for a few grammes in weight, they add a whole new dimension to cycling.