Have you checked out the BF 20/25 style mills. There are various versions but a popular one is the Grizzly G0704 (Grizzly sells out fast and always seems to be backordered). There is a fellow who is a bit of an "expert" on it and has created a DVD showing how to convert it to CNC (and also how to increase the spindle speed to 7200 rpm and to convert it to a Manual Auto Drawbar, etc.). Here is his website with lots of info on the G0704:
http://www.g0704.com/