The infamous hub

Hi everyone! As many of you know, a few of us are following Dave Everett's droid plans and one of the few drawbacks is that it requires the above special motor-to-wheel hub. My question is, do any of you work with machining aluminium, or know where I can get this inexpensively fabricated? Maybe those of us building the Davedroid should get a part run going? It's supposed to be made out of 2011 Aluminium.
I think it would be more cost effective to make a handful of those, but I'm open to suggestions.
Thanks!