Karl:
I started using such service back when Acrobat SDK development seemed like an intractable problem, and I really did not have the time to go through the learning curve. At the time it was called Rent-A-Coder and it was quite good.
They had their grading system, and I often worked with coders who were in the top-10 or top-20 (out of 300,000 coders).
You could search for "Acrobat SDK" or whatever other skill. They were acquired by Freelancer and I am afraid the quality of the service is waaaay down.
Regards,
-Ramon
ps: I also have -somewhere- a list of higher-end, professional programmers, specific to PDF. It camed from PlanetPDF or a similar site. In any event, after I am about to finish my first complete plugin (the copy half of a copy+paste facility) plus an AcroForms Stamper/Filler on Linux, I feel confident that I will have no need for hired guns. I can roll my own. :-)