There was talk about a 3F variant some time back but nothing ever came of it, for obvious reasons. I mean its payload cap would be around the same as the 7F, so it doesn't serve much purpose as is. Still, I wondered what one would look like so I spent a few minutes doing one. This was actually done for the CS T7 as I had already done several LH liveries for it and because the exterior modeling is superior to that of PMDG. Of course that comes at a cost of performance. Might have to toss it on the PMDG 773 just to see what it looks like now that you mention it.
I can't even recall the last time I did anything for a heavy or PMDG. I guess it would be the proposed C-77 that was canned by the DoD and a request for a LH livery. But other than those, I think that's it.