I forgot to add Yankee Hill Machine (YHM). I have a couple guns with their rails and they are of good quality although they have a very very minor hint of purpleish to them (not bad at all but I really like the solid black annodized finish most other rails have...and you pay for it.)

They range from $90-140 for the carbine through rifle lengths I believe. Check Del-ton.com aimsurplus.com and they should have what you are looking for.