Another idea could be for those who like urethane, pair the Rotary Core with the Retrothane cover used on the Grenade. That would move it easily above the remake of the Blue Hammer that EBI is producing currently.
I'm also thinking of a pearl cover with the Neutron Core used in the Shooting/Rising Star covers. That would offer a complete line.
The idea of a low-RG symmetrical product is one that's needed.
My Arsenal (as of February 2012)
Heavy Oil: Roto Grip Defiant: 3000 AB
Medium-Heavy Oil: Track 919C: 3000 AB
Medium-Heavy Oil: Ebonite Vital Energy: 4000 AB
Medium Oil: Track 505T: 4000 AB
Medium-Light Oil: Hammer Brick: 2000 polished