by Craig Browning » Sep 13th, '08, 19:49
Both of the previous replies are on mark; do the leg work first so that you know that you aren't stepping on the brain-child of some other working stiff. Sadly, magic is full of brilliant minds that come up with the same or very similar things with great frequency.
Secondly, I'd track down some of the teaching staff at local tech-schools and see if you couldn't find a couple of students looking for a special "start to finish" product development type project; one will do the technical drawings of the device with another doing the actual fabrication, you serving as the conceptionalist and guide or "overseer" to the project along with the teachers.
I know of many a mage and theatrical production teams that have used Trade Schools as well as the Art & Shop departments of the local high schools to get things made on the cheap. In my experience it's a great way of getting your prototypes up and running. But it's all for not if you've not done the footwork and checked in with a handful of historians and technical experts that may know if or not your design is unique.