There are more than you would think. Over the past couple of decades, there's really been a huge amount of crossover between bjj and wrestling, as well as wrestling and judo, and not only because of the emergence of mma. In Japan it is even more common for amateur wrestlers to be ranked in judo.
Some examples of prominent fighters:
Kurt Pellegrino (high school state finalist, bjj blackbelt under i believe Ricardo Almeida)
Jim + Dan Miller (bjj blackbelts under Jamie Cruz, Jim wrestled DI at Virginia Tech, Dan competed in high school)
Dan Severn (bjj blackbelt, decorated amateur wrestler)
Don Fry (judo blackbelt, amateur wrestler)
Travis Lutter I believe has a background in high school wrestling as well as a bjj blackbelt under the Machados.
Jake Shields is a bjj blackbelt and former D1 wrestler.
Melvin Guillard is a former wrestler who is well on his way to getting a blackbelt in judo.
Evan Dunham was a successful high school wrestler and is a bjj blackbelt.
With MMA fighters the trend seems to be those that wrestled in high school picked up bjj earlier and have therefore had more time to progress in belt level, whereas a guy who was wrestling at the D1 level in college would pick up bjj later, but will be a blackbelt eventually. There's gonna be some badass old guys in 30-40 years, no doubt.
Non-MMA fighters:
Rener, Ryron, and I believe Ralek Gracie (Rorion's children) all wrestled in high school I believe, and are blackbelts under Rorion.
Ken Primola is a former DI wrestler with a blackbelt in bjj who has some great instructional insight into both arts.
There's a guy named Brandon Ruiz who's an international greco-roman competitor that has a Machado black belt.
Not as familiar with Judoka/Wrestler hybrids. I'd imagine it'd be more common in Eastern European countries and Japan, considering the strong judo and wrestling traditions. Though I do not believe he ever wrestled collegiately, Rhadi Ferguson's judo game is very wrestling-influenced, and he's stated that the double leg is his favorite attack. He also holds a bjj blackbelt, and is a blackbelt in traditional jujitsu. Quite the martial arts pedigree!