Hi all, thought I might check in here in case I can offer something.
From my perspective, I believe it's quite possible to build your own desktop machine and have it produce parts with excellent accuracy and a very nice surface finish. The little machine I'm using lately runs a 50 Krpm spindle with pneumatic collet release, and feed is up to 200 ipm. Accuracy is better than .01 mm, the limit of my measuring equipment. The resolution is 0.00025 mm.
It's rigid enough to hold accuracy with this 0.5 Kw spindle with it's max. 1/4" cutters. I wouldn't count on that with a more powerful spindle, or a slower one with more torque though.
Here's a recent clip of this machine in action from my lathe build thread:
Best regards,
Jason