I recently received a ko dotm ironhide by mistake. I've always thought the robot looks like a skinny dude w/ huge shoulder pads. Even when I try to wrap the door around the forearms, he still looks wonky (pic 1 right).
Luckily, I was able to try out many configurations on the ko unit, and found this one to work: The original arm can be moved upward, becoming upper arm. The doors can fold up and become the forearms. This way, the shoulder is much wider (pic 1 left). The only downside is that the transformation requires a little assembly.
The mod is fairly simple, and free:

1. Pop the doors out. Cut the edges indicated by the arrow, so the windows can fold all the way in (pic 2). The fists should fit in the socket.

2. Drill the hole in the door all the way through. This allows pegging in the arm from the other side of the door.

3. From the back, cut the edge indicated by the arrow so the roof can fold all the way down (pic 3). This allows the neck to face the front instead of up (pic 4). This is necessary since the head needs to be moved forward to be in line w/ the arms. I disassembled the head so it can be at the right angle.

Like the others, I also cut the tab inside the chest so chest can be separated wider.