Specs...no. Especially since we don't actually know much technical details about the AT-AT, in the rough size range of this. Any concrete numbers I put out is just technobabble really - you seriously want numbers about how many cm of armor this thing has? I don't know really, but the plating is roughly AT-AT scale, if that helps
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More work on the walk cycle (again, QT H.264):
http://fractalsponge.net/leg/step7_long.mov
Getting better, imo.