I could see adding some gussets, to see if it would help, but I honestly don't see how it could be done. I pretty sure they break from the side to side movement of the rear end housing. You'd need to gusset it on the face where it bolts to the control arm, and the opposite side where the bolts go. A panhard bar setup to positively locate the rear end would probably be a better option. It would cost more though.
I just bought a panhard bar and a steeda rear adj sway that is supossed to be used with the factory sway. This is why I was thinking of beefing the factory sway a tad more by welding the part that usually breaks. Are you saying that it is less likely to break now that I have a panard bar I am going to install?
Welding would probably do more harm than good. The heat from the weld would take out the "temper" in the sway bar, resulting in a bent sway bar instead of a broken one. (Think of heating a coil spring to lower a vehicle) Once heat is added, it weakens the steel.
Umm WOW! That looks like a killer bar! Unfortunately I already bought the steeda adjustable. I got it for $119 and you add it to the existing sway. I figure the difference will be dramatic considering u keep the original sway as well.