I'm pretty sure that Tony Wilbrand and Bronsen Schliep both kept Regents scholarships the whole time they were in school. From Schliep's bio at Huskers.com:
Personal The son of Marvin and Raelene Schliep, Bronsen was born Dec. 13, 1982, and has one sister, Brandy. Bronsen is majoring in business administration/pre-dentistry at Nebraska and is on track to graduate in May 2006. His father, Marvin, attended Nebraska and was a member of the yell squad and club rowing team. Bronsen is a Regents and Peter Kiewit Scholar at Nebraska. He chose to join the Huskers as a walk-on after being recruited by Air Force, Dartmouth and Northwest Missouri State.
In football, in the late 90's Jeff Hemje was also able to keep an academic scholarship, but could do so only because he wasn't recruited in any way by Nebraska, he just showed up at the stadium office over the summer and inquired about walking on. Others in the past have had to relinquish the academic scholarship or when it came to seeing playing time, or they had to be counted against the scholarship limit.