Haven't done this, but a few years ago I used my Dremel to cut up a set of 18:1 classical tuners to fit an older European classical guitar with odd tuner hole spacings, which no contemporarily made tuners matched.
It took a bit of finessing -- I used leather washers to secure and hold down the exposed cut edges, which not only worked effectively, but actually look pretty good.
I risked ruining a set of brand new tuners, but I'm glad I gave it a shot -- they work just fine, and are a vast improvement over the original tuners.
Good luck!