OK, so forgive me if any of this is old news, but I think I've discovered an alternate (possibly partially originally intended) transformation for ROTF Voyager Mixmaster's "battle platform" mode.
I was just messing around with the plethora of joints this guy has and I noticed a few things seem to fit together quite well.
First off, I was wondering why there was a peg on the rear end of the wheel assembly. Then I saw an unused peg-hole on the underside of the cab. I played with it for a while until everything kind of came together. There's even a cutout to accommodate his tanks.
I also figured out that the tab that normally slots into his back to hold up the cab in robot mode can also slot into another spot on the arm assembly. I can't say that I've tried, but I'm pretty sure this would only work with the "backwards" tab that people keep mentioning. Also worth noting is that if you swing the legs around the
sides there is a cutout in his heel that very nicely fits under his shoulder.
It actually sits pretty flush too. I forgot to get a good pic, but Mix's head kind of nests in the groove on the back of the cement chute that's supporting the gun barrel. Lastly, the smokestacks can either sit outside the cab, resting on the mirrors, or inside the cab oriented vertically.