Since I've had a lot of success with treadmill motors on my mills, I've decided to modify and sell these on ebay.

Mill/Lathe Spindle Motor/ Modified Treadmill Motor | eBay

This one is 2.25-2.8 Hp and you can get about 6000-7000 RPMs at around 130vdc. It's designed to fit the mini mill belt drive with a 70mm m6 bolt pattern; but you can attach it to anything. I turned the shaft to 9mm, but if there is any interest for a different size, let me know. The largest size would be 17mm.

I have only one left right now but plan on making some more face plates soon.