They had originally planned to open a park in Manassas, VA back in the 90s. They gave up after local opposition, and the failure that is Disneyland Paris. As for anyone else; Six Flags-No, they have thought about it but they're still in too much debt; Cedar Fair-No, they still have KD; Herschend Entertainment/The Dollywood Company-Maybe, but there's the issue of cash; Hershey-Doubtful, they've never built a park outside of PA; Merlin-Unsure, Blackstone presumably wouldn't want SWP&E and Merlin to compete like that though they did build a Legoland in Orlando; Universal-Unknown, it's possible but then again Comcast owns them now and they may be reluctant to build a new park; and PARC-No, they're barely staying afloat let alone expanding.