Best way to smooth fender bolts?

I have been kicking around an ultra clean / smooth under hood engine bay and the idea of not seeing the fender bolts keeps popping into my head.

I was thinking I can simply take the fender bolts, cut the heads off and weld the studs into the fender bolt locations and nut them from below.

My question and concern is welding the bolt studs into the thin layer of fender lip in a fashion that the metal will be strong enough and not tear when the stresses of bolting them to the car takes place.

Any thoughts?