Have you looked at the price for real PCB prototypes these days? Unless the boards are very large, or very tight design rules (neither of which would mill well anyway), I wouldn't waste time milling protos. You can get a small quantity of boards for peanuts, and turnaround can be as little as a few days. Check out MyroPCB.com - that's the vendor I use for both protos and production. Quality is excellent, and prices are amazing. I get the one-week turn, and the boards are always at my doorstep within a week.
Regards,
Ray L.