I could imagine some sort of Evacuate the Base objective game that could be fun. Sort of a Battle of Hoth Sim where an AT-AT acts as an extension of the round marker. As it approaches the base, Rebels try to escape while Empire tries to attack. Victory points assigned based on how many rebels escape/how many rebels captured/killed/etc by the time the ATAT busts though. The way I imagine it is acts less as a unit but more as a timer... a timer with guns haha. It would need some balancing and tweaks, (though for the rebels in Empire Strikes Back it wasn't a balanced fight to begin with) but that could be a fun custom scenario to run with some friends with a little more thought put into how it would work lol.