Well, once you have rolled over 45 degrees, the elevator becomes the rudder and the rudder becomes the elevator. Most semi-aerobatic GA aircraft and gliders can achieve over 45 degrees of roll, and obviously the higher powered fully-aerobatic aircraft can achieve 90 degrees of roll. The closest I have ever got to 90 degrees was in a Salsbury T76M, at about 80 degrees, which looks Ok from a distance..