ksafin,
If you still want to go the machining route you would most likely need to find a shop that can do Wire EDM machining. It will not be the cheapest route but, you might be able to find a sponsor out of it.
The other aspect of making the rack will be finding a file to make the rack to. I have not seen a file for the rack and pinion. Granted the last time I looked for one was back in November.
After a little bit of research I found a Wire EDM shop in you area that you might want to see if they can give you hand.
Here is there website.
http://www.ligi.com/
I hope you find what you are looking for.