I have never flown anything heavy apart from a few hours once doing an MCC course. I fully appreciate the reasons for V1, runway length, brake energy etc but I can see one immediate reason for rejecting beyond V1. I am delving a long way back to my performance A exam so stand by to be corrected but I seem to remember that you can only use a maximum of 15 kts headwind component for planning purposes. If you are taking off into a headwind of 30 kts and the aircraft V1 is based on braking ability, or runway length, then surely rejecting at 10 kts beyond V1 should cause no problem as the groundspeed is (in this case) 5 kts below the V1 that the graphs have produced.