My guess is 3 or 4 seconds unless you wanted to rip up the wings but what difference does it make? I always knew I could right the 757 with no problem but probably wouldn't have hacked a stopwatch. I'm sure it would do a great aileron roll. I wish I had done one in the sim. My home flight simulator does it very well but it also does a split S to a landing. I've flown in level flight inverted in the 737 real sim over LAX. It has a very good roll rate so assume the 757 is about the same.