I have an idea for a gimmick I would like to have prototyped. I understand enough about machining metal--3D printing won't work for this as it needs to be metal to function properly--to work with a machinist. However, I can't find a machinist to work with. Any leads on magician/machinists who would like to collaborate would be appreciated.

Metal 3D Printing was just released into the public domain.... shouldn't be toooo long before you can realistically get one for around $2,000.

Then you can prototype anything until your hearts content!

http://www.appropedia.org/Open-source_metal_3-D_printer

Not sure which resolution you'll need though, and what resolutions the current printers provide...