I borrowed a friends machine lathe and made "split tube" collar inserts, now I can use all the tiny burs in my pneumatic die grinder. It is not much bigger than a flex shaft, but has much more power, if you can stand the noise. I can control the speed by controlling the air pressure. I can also use the bigger burs in it when I need them.
(I have never been able to keep up with a log, sigh)
Sad to hear about your foot. I hope you get back to work soon.