You might check out the Bass Club of Ft Worth. They are about that size. Here's their link http://www.bcfw.org. We don't have that many boats but you are welcome to check us out at the Granbury Bass Club. granburybassclub.yolasite.com
Forney I think is the closest one on the East side that gets close to those numbers but 50+ boats is a lot for a Club. RHBC has 120 members this year and we are getting 30-35 boats per tournament. I think Forney is somewhere around 40. Not a lot of trails are getting that turnout either. You have ABA and BLT and Media that are normally between 25 and 40 and then Champs and TTT that are 200 or more. Not much in the size you are looking for.