Prowler

The Prowler is the Terran Republic's main battle tank. It's double-barrel cannon featuring a clip size of two is unique among the main battle tanks, and fires much faster than the other tanks'. While this is useful against infantry and slow-moving aircraft the Prowler loses handily against a Vanguard or Magrider. The Prowler is somewhat faster than the other tanks, although the Magrider is much more agile and has superior off-road capacity. Like the other factions' main battle tanks the Prowler can be fitted with High Explosive and Armor Piercing cannons. It also can be fitted with the following co-axial secondary weapons: The Kobalt, The Walker, The Vulcan, The Halberd, and the Marauder.

A Prowler costs 250 Mechanized resources.

This link goes to some extremely high quality pieces of concept art. While they do not have any semblance to gameplay or in-game appearances they are very interesting.