Vague concept stuff (by all means, improve / improvise, etc., these are just quickies):
Heavy Infantry concept. In combat, they raise their shields, slowing themselves down considerably but raising their armor value quite a lot. I still haven't done the rocket-pack version, dunno whether it's even necessary, the way other stuff has been working out. Feel free to try and come up with a good set of knee / elbow joins, but these can be treated pretty much like humanoid robots, I'm not nearly as concerned as I was with the infantry. Might want to make the size relationship between the head and the body a little different, I don't think a real person could fit in that suit at the moment, and they should be about 10 feet tall.
A vague concept for the Resistance's version of the Interceptor. Note the sharply-angled tail fins, reminiscent of the F-22, etc., but with a single engine. Will use long-range missiles as the primary weapon- they're quite expensive, but can defend against Overmind aircraft with more reliability than the Overmind's Interceptor swarms.
Scoops metal, dumps it into the little cart, the cart goes into a "smelter", smoke comes out and a sound effect plays. I hate the turret, and I actually have a pretty good turret for the Resistance's Advance Bases, so I'll probably use that...
A counter to the Sniper (which the Resistance actually kind've needs, at the moment), this is like a walking LaserCannon, direct-fire, and has to halt to fire. It's too wide in the front view, needs to lose a bit to feel right, and I'm thinking it might be really kewl to have hydraulic spikes along the sides of the legs that slap into the ground when it deploys.
The Overmind gets a drone carrier, launching swarms of drones, Invid-style. I already have the LUA to do a Protoss-style carrier, it's just a matter of having the model.
The main need, design-wise, for the carrier is that all of the holes are exactly the same size. I'm not at all in love with the basic design, although I liked the triangular rear "command deck" concept, it feels right for the Overmind. They don't even have to face upwards, although if they're going to be angled, they should be modeled so that I can turn them, just to keep the hatch-opening sequences from being a nightmare.
Vague idea for a Resistance transformer unit. I think it might be fun to have an air / land mecha like this. Would use LUA to change forms, I have a plan for how to do a transformation that does not use the Morph Gadget, which I don't like a lot.
More coming...