Allen line: Who was Michael Dunn?

Michael Dunn is very much a brick wall ancestor. I don't know when he was born, when he died, who his wife was, who his parents were, or when he or they or their ancestors came to America.  At this point, all I know about him is from a short biography of his grandson, George Washington Dunn, which states that his father, Lemuel Dunn, was the son of Michael Dunn, a native of Virginia but of Irish parentage, and a noble defender in the War of Independence.  That's it.  That's all I know for sure, and of course the biographies that were published in the late 1800s are known to not be 100% accurate, so this may not be 100% accurate, either. 

However, working on what little "information" I think I have, I've found two Michael Dunns in Virginia during the time period I'm researching (roughly 1775 to 1800).  One is a Michael Dunn who married Elizabeth Cheney in Maryland and went to Wythe County.  He may be the Michael Dunn who was in the militia in Montgomery County, Va, but the other facts don't fit, because the Dunn family was in Maryland for many years prior to the Revolution.  I haven't completely ruled him out, but he's not my top candidate at the moment.

I've found another Michael Dunn to consider. The earliest I can place him so far is in Henry County, Va, in a 1782 tax list.  That means he would have been born by 1764, at least, and he could well have been born quite a few years earlier.  There is also a Michael Dunn who was taxed in Botetourt County in 1984, which is a couple of counties away, or maybe just over a mountain ridge.  Patrick Dunn and William Dunn are also in Botetourt County at the same time. Patrick and William are noted as being in military districts, but Michael is not. Perhaps he was too old by this time to be eligible for military service, although there are other reasons he could have been excused also. 

The only other reference to a Michael Dunn that I've found was in a list of soldiers killed at the 1791 battle known as "St Clair's Defeat". A James Dunn was also killed that horrible day.  I don't think this would be our Michael Dunn, or surely it would have been mentioned in George Washington Dunn's biography, but there is always an outside possibility so I can't discount it entirely.  The fact that I haven't found a Botetourt-Henry County Michael Dunn after that time period is a little unsettling. 

I need to do some research on William Dunn and Patrick Dunn, to see if more information is available about them, and also search more in Kentucky for Michael Dunn.  Lemuel Dunn was married there in 1809, so it's possible that Michael had gone to Kentucky after he disappeared from Virginia. 

Here's the line of descent: 

Michael Dunn and unknown
Lemuel Dunn and Sarah Reid Campbell
Margaret Dunn and Archibald Allen
George Allen and Nancy McCoy
Edward Allen and Edith Knott
Richard/Edith/Vernon/Tessora/Corinne
children, grandchildren, and great grandchildren

If you know, or think you know, anything about Michael Dunn, I'd love to hear from you.