I am not sure you will be able to find a place that will guarantee your own meat back in jerky and sausage.
They tend to make big batches to and return the proper poundage to the customers.
I know Schusters will, but I don't know if they will take meat that is already boned out.
If you've already gone to the work of boning it, you might consider buying a meat grinder. Making your own sausage isn't too hard, but you'll want a good sausage stuffer. I never had good luck with the ones that just go on the end of the meat grinder, so I bought a dedicated LEM stuffer. It's awesome.