The folks at Piranha Games have revealed that you'll be able to pilot the 50 ton Hunchback mechs in MechWarrior Online. In this video they show off the 4G version of the mech which includes 10 tons of armor, two medium lasers, one head mounted small laser, heated seats, and a giant AC/20 cannon. The mech is a nice mix of speed and power which is very effective on the battlefield. Here's a short video of the Hunchback in action.
Of course that's the stock Hunchback, you'll be able to take that sucker into the MechLab and tweak that sucker until it's the perfect match for your play style. Remember those who purchase a founders package will get immediate access to the MechWarrior Online beta which is going on right now.