chassis options:
light (basic model 1 - good scouting tank; faster because of less weight but weak armor)
heavy (basic model 2 - battle model; slower but can take some more damage)
improved (what personal armor is to soldiers - alien alloy put to good use)
energized (just like power armor - alien shielding technology)
propulsion options:
tracked (that's caterpillar; slow but capable of crossing every terrain easily - and crushing aliens)
wheeled (faster, but cannot cross rough terrain or fences)
hover (alien-derived tech
[for those who like it: bipedal or quadrupedal could be discussed. or even more legs. good speed, can cross most of terrain types - and can literally kick some alien butt] :happybanana:
turret options:
gun (slow reload, quite accurate, lead or depleted-uranium slugs)
machine gun (burst fire, spreads some, mow-'em-down)
missile (perhaps even more than one type? like "smoke", "standard", "high explosive", and later even "stun gas")
[perhaps another one: flame thrower?]
laser (has to be researched)
plasma (you know what it is)
quantum missile (that's what it's called, isn't it?)
...now the idea would be that you can choose ANY combination you like. so you could even build a hover tank with light armor and a machine gun as a superfast scout, or a caterpillar-driven power-shielded monster with quantum missiles.

what do you think?