The 737 FCOM i have available (20.05.2010) states
"Any speed between V2 + 15 and V2 + 25 knots results in approximately the same takeoff profile, it provides a safe margin above stall for a 30° bank with a 15° bank overshoot. Crosscheck indicated airspeed for proper initial climb speed."
Which equates to a margin sufficient for up to 45° of bank. However there is a bank angle limitation that states max bank angle after take off is 30°, unless your speed is below V2+15 where it is limited to 15°, but still with a margin of 15° of overshoot.
The same applies to cleaning up, a safe bank angle of 30° with an overshoot of 15° is assured once you're above V2+15.