The JLTV setup that
@Maxman1 posted is a beast - the mortar is recoil dampened in the mount, and it is gyro stabilized to allow for a lot more than what a ground mount offers. But it is HUGE, and overkill for any light role, and under armored for what I would want for a Mech/Armor formation.
Rockets and Recoiless Rifles are ideal for that sort of thing...
Plus the truck doesn't need to be constantly replaced by stealing form other units