The Decepticon beast Headmasters, Wolfwire, Mindwipe, and Skullcruncher. Interestingly they all have cockpits:

Though, Mindwipe's cockpit has a rather different orientation, and Skullcruncher's is really weird.

Since these features exist, I figured I'd tinker around and see if I could come up with accompanying vehicle modes. Here is what I came up with:

For Wolfwire we take a little inspiration from Voltron/GoLion

Mindwipe is a little trickier with the Bat head stuck in the middle of everything.

For Skullcruncher I just took a cue from the TR Alpha Trion ship mode.

 

I take it you haven't had the original Headmaster versions of the toys before.

Other than the fact that original Skullcruncher's cockpit was in his mouth the cockpits are authentic to the originals.