We are going to be starting a few small tight tolerance mini mills.
What I am wondering is what is the best type of feature to implement?
Dove tail.... to much friction..... I feel
linear bearings of sorts...... what?

The machine has to be as friction free as possible.

Also anyone know of a good source for ball screws around 1/4 diameter or so?

all ideas are welcome!!!

I'm sure you can some ideas from here:

http://www.cnczone.com/forums/showthread.php?t=30262

Thanks for the input.