Boxers
I don't usually write about BREEDS of dogs. I write about dogs in general.
But, this being a special case, with Uga the seventh dieing, I might add that usually Boxer dogs are good natured, and they have a bulldog face.
Like many purebred dogs, they have their health problems. It might be possible to request a boxer mix from petfinders or a shelter. Make sure it is really a boxer mix, not a fighting dog.
And test the dogs behavior before giving him the Uga name. And IMO a mascot should be neutered before puberty, why take chances?
Or maybe a guy in a bulldog suit would be a more entertaining Bulldog?
http://www.petfinder.com