I’ve got an old ~97ish Fire mountain frame in the garage that served time as my winter SS, I welded a Disc mount to the back end ages ago and then just didn’t do anything more with it.
I’ve had a few ideas over the years about what to do with it, maybe Grind the canti’ bosses off possibly even cut away the seatstay brace to improve clearances, then maybe use it as a 700c road/gravel/hybrid type bike, maybe try 650b on it or just build it back up as a 1x? – 26er hack, for which I would now need to find some wheels again, and I already have a 1×9 – 29er hack…
The sad truth is it’s probably just going to sit in the garage forever now, I can’t inflict my terrible welding on another human in good conscience, so unless I do something else with it, it’s a scrapper/wall art. I have pretty much zero need for yet another MTB currently, certainly not a 26er anymore as all my bikes are on some flavour or another of 622mm rims.