If you're willing to compromise on the engine, a fuel cell engine will get you a forty ton tracked vehicle with the requested four tons of cargo (I assume infantry), 4/6 mobility, a turret mounted large laser, bow mounted machine gun, and 8.5 tons for armor or possibly some secondary weapons.
If you're willing to compromise on the vehicle's mass, a 50 ton vehicle with an ICE will get you all of that, but only 6.5 tons for armor or secondary weapons.
If you're willing to compromise on the motive system, a wheeled 40 ton chassis can get you all of that, except you're down to five tons for armor or secondary weapons.
If you're willing to compromise on more than one of these things, well, you get more. If you're willing to compromise on none... you get nothing better than the goblins that already exist.