Does load factor affect roll rate? To be clear I am referring to a given aircraft at a given weight, speed, attitude, etc everything else the same except one is at say 0.5g and the other at 2.5g will there be a difference in roll rate if both have the same aileron deflection etc. 

From my reading I think the answer is no but I am looking for something definitive. The question arises because the typical nose low UA recovery is UNLOAD then roll and recover to the horizon. For what reason is the UNLOAD? Some have suggested that it is because you will get a better roll rate to get the wings level. This I am not sure about.

I believe the main reasons for unloading are that (1) you want to avoid asymmetrical 'g' loads and (2) when holding a large amount of elevator force the pilots ability to input up to maximum aileron deflection is limited.

So I would appreciate someone confirming or denying if there is an aerodynamic reason that roll rate is affected by load factor?
One of the best reasons to unload before using your ailerons is to make sure you are not 
stalled.  If you are, using ailerons could reverse and make you roll the opposite way.

Ailerons can be evil when used uncoordinated with rudder, yet very helpful rolling out of an inverted dive.  The danger increases if the aircraft is yawing and near stall.  So it is much safer to recover in 2 steps, unloading first.