Making a Zoid

Hi, I've been passively working on making a mech, pretty much inspired by Zoids, for a while. I have a lot of the wiring prepared, and some of the parts.

This is mostly going to be made as a prop, for conventions, to promote a game I'm developing. As such, side-stepping and other "luxuries" are not as important as finance currently. I have a couple ideas down for the structure, and want some feedback, because it effects both: What parts to get, and how the wielder should build it: Especially since I may want to add side-stepping much down the road (if it's too difficult/expensive to impliment now however, I'd just remake the frame).

Anyhow, the mech is to be a quaraped to ride inside. The chasis for the first version will be mostly made from resin/eva foam/plastidip, to keep it lightweight. The actual place I need opinions on is on the legs: Stepper Motors with Jansen's Linkage, or Linear Actuators? 

I know I have one Linear Actuator already that could handle the load of half the weight of the mech+pilot, and would use DPDT relays to control them. I like this idea because linear actuators will not collapse from loss of power like their hydro/pneum. counterparts. Granted, they're slower, but it's mostly as a promo/prop, so I'm fine with that, and plan to adjust speeds for them with dimmer switches.

On the other hand, the only other things I was looking at using would be a stepper motor, with a rotary Linkage like Jansen's.... it would result in "cleaner" strides, and probably require fewer motors (1 per leg)... but I do not know:
1) The cost to torque ratio for stepper motors.
2) How to calculate torque for running a linkage.
2) How to look up gears for stepper motors, to gear up or down as I may need. I plan to run the motor to the linkage by a belt, in the chasis.
3) If stepper motors would collapse without a chage, or if they often remain stiff on power loss/malfunction...
4) If the power is lost causing it to "cave", would a well-crafted linkage still rotate and ease the mech into a stable "rest" position.

 

I would like to help with as much as possible. J have a great interest to say the least.