Well this is a pretty late update, but I did manage to machine new dropouts:
They work very well, probably capable of supporting double the torque I have the motor produce at 80V 200A battery, 550A phase.
Pretty happy with the bike, when it's working well it's about what I imagined, very fun and almost too powerful. Though I have some problems. Firstly, as some of you thought, the backpack is very heavy, for short rides it's fine with a very good backpack, but not for longer ones, which i's why I'm getting a support for it mounted to the seatpost soon.
Secondly, as I managed to put everything together over a year after ordering the motor, the ferrofluid QS applied had dried out, and when spinning the motor suspened in the air you can hear some sort of rubbing a few times a revolution, sounding a bit like a brake rotor rubbing (although it isn't). I managed to disassemble the motor to check, and apart from some iron shavings from the dried up ferrofluid, I could not find anything abnormal.
The last and worst problem is that I have started experiencing some cogging and "clicking". Had none of that when I had just finished the build, but now when going past like half throttle at speeds over like 15mph I can feel a "click", almost like a chain skipping a tooth, loosing some power, and I think I can feel it isn't as zippy. One time during a ride when it was happening I switched to the other hall set, which made it much worse, cogging all the time, to then switch back to the first hall set, and this time it worked like it should, no clicking, cogging, ultra smooth and zippy. What can be the cause of this? Shouldn't be bad hall sensors right? (At least one of the sets), but maybe the controller?