Okay a lot to say on this.
2 legged mech a la battletech in real world combat? No chance. Too many issues with stability and hight.
That said what i can see is some sort of infantry Exo suit. Bassiclly imagine an infintrayman sat or stood inside the torso of a 2 legged mech, with him moving himself with moving his legs/arms inside the torso to move the mechs legs and arms. Get the system right and you get all the advantages of power armour, but none of the limitations, Shoulder and hiop joints no longer have to compromise on motive power and armour to let the human anattomy fit. That infantryman goes from a very well armoured human to the equivelent of a decent non-MBT AFV. They'll also be able to run furthar faster and carry a heavier weapons load. I imagine weapons on the forearms, (so you cna have free hands). The left has a 50 Cal + an automatic extended range vershion vershion of the generic modern underslung rifle grenade launcher, both belt fed from the bacpack, whilst the right arm holds a weapons tube capble of functioning as a luancher for shoulder luanched level SAM's, ATM's, and light Mortar shells, again backpack stowage.
That bassiclly gives you a platform with the firepower of a kjeep full of infantry, but the armour of a much heavier unit, and it's going to be significantly smaller. The main issue is the power source.
As for ank like mechs. One issue modern tanks do have is that physichs means they can't have infinite width tracks. The closer the track edge gets to the centre the greater the stresses get when truning, (this applies even if you use multipule tracks), and the stronger the track and sprockets have to be. there comes a point at which for weight a given leg based system provides better ground preashure for it's weight. A simple solid or semi flexible plate with spikes can be a lot stronger for it's weight, and with the right locomotion system the rest shouldn't be too heavy or too tall, (it makes a nice engeneeiring challange to think about).
An abrams for refferance has abotu 1/5th the peak ground preashure it's dimenshions allow. No leg system is ever likliy to get about 50-60% the avalibile area used. But it still adds upto a drastic increase in peak mass, roughly 200 tons, mayb a bit more on he same length and width. Hight is equal to the amouunt of upwards movment you want in the legs to clear obstacles + the clearance of the main body off the ground you desire, (which need to be the leg lift plus whatever you deem necessery). This does give it a larger profile, but where talking on the order of a 100% increase in highet over an abrams, not the +300% or more MW like to throw down. the design is going to have a bit more surface area than an abrames of the same basic dimenshions, but not a massive amount, so square cube klaw and density being what it is it would have grater armour than an abrams. Which makes it perfect for urban warfare.
Another application would be varied support stuff, like missile carriers and SPG's. Current designs have to balance mobility, (via ground preashure), vs. the size and quantity of weapons. Having a chassis you can moutn a patriot luancher & rader system on that can fire the lot whilst moving, or a long calibre 200mmm gun/howziter combo is quite valuble, (and the profile is drasiclly less problamatic). That said i'd expect lower peak speeds compared to tracks, though not to the degree some would think.
Edited by CarlBar, 25 June 2012 - 03:33 PM.