I'd suggest a few places.

Did you try large machine shops? I know that Chalmers & Kubeck is constantly on the lookout over on the Philly side. There's one right down the street from my employer called D.C. Fabricators in Florence.

Did you try going through the engineering firms themselves?

Also, did you try seeing if any of the engineering professional societies have meetings in the area that you can get in to that might land you a job? A lot of these are not worth it, especially if they are mostly college kids. But there are a few out there that work wonders, but they're low key (hard to find).

What about surveyors? Those guys like going out and doing stuff outdoors and a lot of them can't stand doing the CAD side of things (office work), so they like to have a CAD guy do that for them.

Personally, at the major companies I've worked for, we sort of had a list of mechanical designers (CAD jockeys) that we farmed the work out to for detailed drawings. We usually didn't even have an "office". We just emailed & faxed back and forth. But to land these ones, you're going to have to network hard.