Just a thought: An armor powered by batteries that uses a chassis, etc. When used in combat, it adds strength and movement points and reduces encumbrance, but drains energy. Otherwise functions similarly to a suit of steel armor.
Strength requirements are actually less than steel armor, but you only get the benefits when you activate the armor, in or out of combat. When armor is not active, movement speed decreases and encumbrance increases. When active, movement speed increases, Encumbrance decreases, etc etc.