I've seen 1-2 other Hummer billboards, not including at least six Dallas-area radio stations.
This is almost a Hummer, as the Escalade pickup truck is a lot like the Hummer SUT (should be renamed Suburban Large Utility Truck or SLUT). An Escalade SUT was making it hard to get on the freeway and apparently proud of his behavior with this plate:
MF 4 