Any examples of rural regions (I.e. <50K population), not in close vicinity to a college/university, that are successfully producing startups?

What kinds of start ups? You may find some scattered IT here and there but I highly doubt you'll find a lot of high tech. There are reasons why the term industry clusters was coined. High tech requires more than just facilities and infrastructure, it requires people and teams that are more than 10meters from each other start to degrade in performance. Simple reality.

Also, hi tech heroes tend to want the thrills of a big city or a city and if not them, then their families...and good schools and so on.

Setting up in the middle of no-where means a lot more expenses when you need to hire talented people and relocate them.

As for Russia, out in the middle of no where we have a lot of farming start ups: huge intensive growth orchards in Chechnya, with a German partner. Angus ranches, fully automated, out in south western Siberia and so on.Agriculture or mineral/petro extraction rules in those areas.

I think the best people to talk to about this would be my friends Andy Stoll and Amanda Styron of http://seedhere.org. They just completed a bus tour with Steve Case (founder of AOL) called The Rise of the Rest that was focused on building entrepreneurial communities in smaller population areas. Andy and Amanda also consult with many small communities similar to what you are describing that are working on creating community driven entrepreneurial initiatives.

Let me know if you need an intro.

I don't have a direct answer to your question, but I'd like to add this to the mix:

Rural regions without colleges tend to have populations focused on production, not R&D. Can these regions produce startups? Of course. But it won't happen in the quantities it does in urban areas.

I think the recipe for high quantity/quality startup production is: High population (populous areas will have more of everything, including startups), high education (startups require a R&D mentality), high salary (someone's got to pay for those startups), and high number of head offices (management experience).