The steamrolling tactic consists in en masse building of a few complementary armored types, and sending them rampaging straight away onto the enemy. Its sole advantage is its sheer brute firepower. It's also plain fun to smoke the enemy in an overwhelming mass of units. The downsides are, however, numerous and annoying. It is incredibly time and resource consuming, provides for completely inflexible formations, and makes easy prey for any area damage weapons. As a matter of fact, this tactic is only an option in a team game, and then only when you have already eliminated an opponent and taken over his resources.
Allies
A mix of Cryocopters, Apollos and Guardian tanks will offer you decent results. On sea, swap your Guardians for Aircraft carriers.
Soviets
The most suited faction for steamrolling, as their "mass production" protocol reduces production costs by 25%. Swarms of Twinblades, MiGs, Bullfrogs and Artillery units will serve you well.
Rising Sun
Focus on the almighty Shogun Battleship, along with some seawing support. If your opponent is out of range, try Striker units.