Paul Wall yes, Bubba Sparxxx, no. Bubba Sparks was more of a novelty act that backdoored Timbaland beats. Bubba was talented, but I don't really think people would accept his gimmick. He kind of reminds me of Pink in that he was forced to put out a sound that 'wasnt really him'.
Paul Wall was one of those white boys that grew up around blacks and his audience is organic, so Paul Wall would be big in Texas stil. especially if that style of Texas rap was still popular. The difference between Paul Wall and Bubba is Paul Wall that Paul Wall was really him while Bubba transformed into a hillbilly country rapper.