So Optimus now has a Velocitron form (Bendy Prime repaint) and a Jungle Planet form (BWX Optimus Primal repaint), but (as yet) no new form for Giant Planet, so I'm planning one of my own.
[EDIT]I've been informed that the Bendy Prime repaint is his Gigantion form, according to his key bio, and he doesn't actually have a Velocitron form. Oh, well. This fits the Gigantion theme better.

[/EDIT]
Behold, the digi-concept art for my future project:

The blue won't be quite so bright (I couldn't seem to get the shade I wanted without losing all most of the mold details) and the "wings" will only be grey on the sides facing forward in bot mode.
The crane will be darker blue than Mudflap (same shade as bot mode's hands and legs), while the non-blue parts of bot mode will be all but completely hidden in alt mode.
Now all I need is a second Mudflap...