I just found just the study I was looking for. This study examines the proportion of Florida alleles in multiple Virginia lakes. In this one study, performed in 2005, on average, Virginia bass possess 47% Florida alleles. Briery Creek Lake, the top trophy bass lake in Virginia, was found to have 61% florida alleles.
http://www.seafwa.org/resource/dynamic/private/PDF/dutton-251-262.pdf

I'm actually surprised the number aren't that different from the allele percentages you posted from Texas. I pulled some info below on Lake Fork. In surveys performed between 2006 and 2009, Lake Fork contained an average of between 48 and 53 percent Florida alleles.
http://www.dallasnews.com/sports/more-sp...unkers-down.ece