so, from what I'm gathering the mountain plate is an armor bonus of +10 correct?
The mechanus gear from planar handbook is weighed at 75 lbs, cuts speeds in half and that's it and it is a +10 armor bonus, with a 0 max dex and a -10 armor check. However there's no other restriction on it, other than the handsome sum to get it (1750gp). You can run, albiet at the standard x3 for heavy armor. And even dwarves? The mechanus gear doesn't do that.
And what is battle plate, I imagine +9 armor bonus, +1 max dex?
Must get Races of Stone...
I'm with you, that weight must be a typo or something, unless you are wearing an engine block for armor, i don't see that weight ever being tossed around. Although D&D weights are really funky as is.