CatusWren, I'm offering this suggestion stemming from "I wish I had done that way back when mine was a pup". Since he's still limping and obviously sore and since your regular vet did not find anything and suggesting another two weeks based on just a physical exam, If I had to do over again for my boy with all the limping that he did as a pup, I wish I had insisted on getting a good orotho specialist on board.
Maybe this limp just needs more time, maybe it's just pano, maybe it could be Lymes or another tic disease, but an orotho would be better equipt to cut through the time to pin point what is going on. If I had it to do over again I would at least get a good orthos initial exam while in the two week wait and see period and not have wasted so much time just waiting and seeing.
Finding one and with an initial exam does two things, a second opinion and the fact that if you ever need a good one in the future, you already have one. The latter imho is worth the expense as insurance of not wasting time in the future if needed.
When I think back to the kind of manipulations that the vet did with my guys legs, I often wonder if it was the correct things to do. Some were just to try to illicit a pain reaction. One vet tried to read his pain via pupil dilation. The manipulations seemed over harsh and non productively informative for what she was hoping to achieve.
I am a wait and see but only for a day or so. Just my thoughts based on my own experiences.
"If you can't see his soul when you look in his eyes, then you need a seeing-eye dog"