Yeah, sending it back to Canon claiming their repair was bad is not on. Neither is filing under home insurance - it's likely just another $125 to get it fixed again, I'm not monkeying with insurance for that.
For all the comments on getting better lenses, the 50 was actually the best lens in the bag! Also along for a ride (and unharmed apart from the step-up ring previously mentioned) was a 75-300 USM III and a 28 f/2.8 - neither exactly known for their robust construction. I think this was a combiation of the 50's weak A/F system along with it being mounted to the camera and pointing down when it hit, so it took it from both directions.
While the plan definitely is to improve the lens selection over time, I don't expect to change in the 50 1.4 for a 1.2. I'll look at a better way of packing things and maybe look at some other bags to try and reduce the risk. Otherwise, my butt is well and a Canon technician gets to work another day - all is fine in the world. Thanks for all the suggestions.