I can do smaller runs no problem. I can fit parts on to the un-used skeletons of my current production stuff
My biggest hassle with the smaller jobs is the running around town. I am currently without a vehicle and public transport turns a 20 mile trip into a half day affair.
If you want I can laser and bend the test parts for free. If it works, I will send you the prices for fabrication.
As far as the pipe issue, not much you can do with the sizes, Where I am at it is a english/metric mix but a little more heavy towards metric that the States.
Pipes and bar stock here are generally english sizes. The machinists prefer english sizes cause if they are making something in metric 25mm size they get 25.4mm (1 inch) size and have some stock to work with for surface finish.
Note for CNC tolerances, bending is within one degree, laser/water jet is within 0.2mm for 2mm and goes up the thicker the material.