Update: It's fixed!
Suspension shop said, "We'll call you back," but never did. Welding/Machine shop said, "If it's attached to the vehicle, NO WAY!"
Finally called a regular mechanic, figuring he should at least be able to recommend a welder. Mechanic said, "Can't say for sure without seeing it; bring 'er in." He took one look and said, "Huh, never seen THAT before. I've seen these rust off, but never snap off like this. Yeah, I can weld that up, no problem."
So, bottom line is, it's fixed and we back in business!