So I finally took a moment to upload my design for Megatron's newest appearance in IDW comics, from Robots in Disguise. Included are my ideas for colors, but I think Josh used colors that were slightly different for the book as I only ever shared a b&w drawing with him.
This is the body he was rebuilt into after shedding his ruined stealth jet body around issue #14 of RID.
Was intended to be something of the quintessential Megatron, mixing the look and feel of his G1 design with more contemporary designs like the one from Stormbringer and Megatron: Origin.
Megatron was also designed to have a look that could fit technologically as a modular unit of the rebuilt Devastator, sharing certain design features with the Constructicons from RID.