411A
yes, if you encounter windshear on the runway and are running out of runway you should rotate 1000' prior to the end of the runway, EVEN if you are below V1/VR.
You should also set FIREWALL POWER/THRUST.
If you doubt this, please do some research.
(all of this assumes that you are running out of runway...a situation that the comair pilots were facing)
Airliners will fly below V1/VR, just with a loss of certain protections and performance, but in this case the tradeoff would have been justified.
411A: what would you do if faced with stagnating airspeed, & running out of runway? (on runway windshear scenario)