Originating from the region that is known as "Kentuckiana" (I'm from the Indiana portion), I'm not that surprised. There are nooks and crannies of small valleys there that, in my childhood, I spent much time. I've known people there that could be mistaken for Bagginses and Brandywines, even a few Tooks! They kept pretty much to themselves.
Just a thought.
I've just come across your speculation and thought you might like to know that I presented a paper on this subject at the Tolkien 2005 conference last month. The conclusion may be found in my title: "Hobbit Names Aren't From Kentucky." Barnett's stories may have contributed a teaspoon to Tolkien's inspiration (but no more than that), but he picked his hobbit names from their occurrence in England, not Kentucky (regardless of the English origin of many Kentucky names). And the surnames he used for hobbits are, in U.S. distribution, neither particularly characteristic of nor distinctive to Kentucky.
Wow. I feel slightly more secure in my professional (er ... maybe not quite yet) instincts now. Thanks very much.