One thing I forgot to mention was that the chainline adjuster does not allow for a lockring. Due to the fact that it screws onto the freewheel hub, a lockring would cause the whole assembly to spin off.
They are geared for track use, but I believe some people have used them on the streets(I use a brake when I use mine on the street)

I have seen a couple cassette versions on eBay, such as this one.
http://cgi.ebay.com/Specialized-Tris...QQcmdZViewItem