How about mods for the sunderer so it isn't only transport:
Artillery: The sunderer gets an artillery gun that needs to be setup. Balancing as discussed in:
http://www.planetside-universe.com/s...ad.php?t=37108
Mortar: Similar to artillery but with much shorter range and doesn't need setup.
Quad cannon: Giant machine gun suited for either anti-air or anti-infantry along the likes of the unit from "command and conquer generals".
Anti-tank cannon: Like the quad cannon but meant for tanks and sunderers.
It may be hard to balance some of these but i think they could be really cool.