One reason I do not have a 10mm is because I just cannot see taking the plunge for twenty grains or two hundred FPS over what a forty will do. 10g of Longshot behind a 155g used to be a listed load in the Hodgdon manual, and it specifically stated that it was not for guns without fully supported chambers, probably would have been legal ramifications had they said "Don't shoot these in a G22, idiot." I bought some new virgin brass and some Gold Dots and loaded a hundred. I had a 6" Lone Wolf barrel for my G35 and I think I recollect they went 1,535fps and they were fine. Fired one (without a mag in the gun) in the stock Glock barrel and it looked like it was ready to give birth.
But as we discussed in another thread, everything gets stubbed off in the length that is hidden AIWB/IWB, the 320 Legos might be interesting. But like you, not sure it is something I might toss money at.