Hey there,
Recently, I tried my hand at several Mech Armor style MOCs to see if I could put my own twist on those models, and created this duo. The idea was to design a $20 pack of two armors like the 76219: Spider-man & Green Goblin Mech Battle but to go beyond the simple "duo-pack" concept. Rocket's walker-type mech can convert into a cannon to use on War Machine's shoulder, as seen in the pictures below.
More pictures and (free) instructions are available on my Flickr gallery. Enjoy !