Finally got around to making use of a junker Thunderwing. I got it after swapping a good spare Thunderwing with my son, whose copy had cracked shoulders.
The original chest had gone on to my leader Thunderwing. I made a new one from some parts I found (I have no idea where it's from).
I used what seem to be CHUG Perceptor shoulders, which the arms fit well on to. Again, I have no idea where those shoulders came from.
I filled the feet in with sculpy, and reversed the thighs to create some more points of difference.
The head is from a junker Gundam (the only one I've ever bought), the missile rack is from one of CHUG Scourge's gun and the cannon is from a junker Revoltech Megatron back cannon.
The moral is: never throw anything away!

I like to think of this as a mix of G1 and Stormbringer designs.