I present
the Ripsaw:
While it was built by professional fabricators, it was still built in a rented two bay garage. And while it's built to be unmanned, it does in fact also have a cockpit.
Just steal their design, scale it up a bit, and have two track pods on each side instead of the single ones this one has.
And remember kids, as long as the cannon cannot fire real shells, your tank can be registered on the street.
I will now await the build thread. . .