I will second the recommendation for Binkley and Hurst, as I also saw Chim's post in the past and bought the shanks, teeth and even the cutting edge to build one.
One note is that they have a few different style teeth you can buy. The ones I bought are FFC teeth and my bar looks like the FFC bar shown in this picture (posted by rancar some time back). My digital camera is broken so I can't take a picture of it.
I dealt with Kevin in parts and he was very helpful. I ordered 1/2" x 4" x 45 1/2" cutting edge ($28.66), Six shank w/teeth already installed their part # CAS B504447 ($15.71/ea.) and $21.15 UPS shipping to NY for a total of $144.07.
Paid a friend another $50 to weld up and was done at ~$200 so I figured I saved about $100. Of course I don't have any welding equipment or it would have been more.