Went with a pupil to try out some violins for them last week at my local shop, when we we discussing various options one of the luthiers there pointed out that they were now fitting certain instruments with fine tune geared pegs.
I had not seen these before and was quite impressed! So easy to turn, you can do it with just two fingers, and the pegs can't slip
They had two different types, one looked just like normal pegs, the others a bit less so. I thought these would be great for anyone struggling with slipping pegs and general tuning issues. Might be worth people looking into them