mixmaster has been the trickiest so far, i originally wanted a g1 style devy foot, but i think what i ended up with is a much more simple transformation.
using a modified hinge assembly off the back of energon snow cat, and a dollar store toy mixer truck and a few random toy parts, i think i have come up with a good compromise.in alt mode the mixer locks into the hole between the arms with a small peg, and folds tightly behind his back in robot mode. i still have yet to fit a connecting port in his chest cavity, as its probably the trickiest to excecute.