As far as I know, there is only one 1/72 group anywhere in the USA up in the Washington State area. Probably the reason why most people build to 1/144. Heh.
1/96 is concentrated around Ohio and neighboring states. I believe all of the 1/96 battles have been fought in Ohio. It is a somewhat new format so it will take time to grow. 1/144th is the most popular with Texas having two formats in it: MWCI and Big Gun. All is not lost though. All it takes a a couple more people interested in your area to start a small battling group in any format. You could be the first 1/72 group outside of the Northwest.
heck you might even be able to convince some of the big gunners in Texas to join you in starting the 1/72 club down there. at the very least they will help with the building and arming of a ship. Might consider attending the NTXBG's big gun open event. I believe all formats are welcome and the knowledge base to learn from will be awesome.