RE: Other places in Owensboro, Ky
Other than Moonlite, Old Hickory Pit and George's Bar-B-Q on U.S. 60 (the latter on the one-way part of the street going west) are probably the only two other good barbecue places in Owensboro. They have been overlooked in the past, but because Moonlite seems to be de-emphasizing the quality of their barbecue in favor of their overall food bar, these two places are well worth checking out.
Seems like wanderingjew has given me a good reason to drive east.
But to answer Robearjr's question, as best as I can tell, at the moment the barbecue mutton belt extends as far west of Owensboro as Waverly, Kentucky, just before you get to Morganfield, Kentucky on U.S. 60. After that you mainly run into pork country.
At the moment (7-11-07), that belt doesn't extend any farther than Henderson because Peak Bros. Bar-B-Q in Waverly has still not been rebuilt yet after their November 2005 fire--although they have plans to do so soon.
In Henderson, you can try barbecue mutton at J&B Bar-B-Q (Washington Street), Thomason's (Atkinson Street), Gene's (Green Street) and Ralph's (Green Street). It's not as good as Owensboro's barbecue, but it will do if you are really hungry and not too picky.