The Hasbro exhibit at a Hong Kong convention has included the other two Siege Powerdashers to go with the "car-dasher" Aragon that was revealed at SDCC - we have the "drill-dasher" Zetar (reworked Brunt) and the "jet dasher" Cromar (reworked Sixgun).
No details yet on when or how they will be released, but were noted as being on display with other Generations Selects toys, so would at least be exclusives somewhere.