This is a very good idea. I have used college kids for background vocals; I've hired a student string quartet for a project, etc. Jazz violin is not something widely taught, with the ability to improvize. Especially when you live in rural South Dakota and the nearest college is 100 miles away, that being a small one. But you're right; college students are a very good source of musicians for cheap; and they're often very good, so long as they have an exact score to follow. Not many improv greats in my part of the country I'm afraid.