I've been looking around at some thunderfire alternatives and scratch builds, and then wen through my bit box looking for things to help, and so far I think I've got a plan together. A couple of plasma pistols, some Valkyrie bits, and away we go!
Starting with the techmarine (because it's easier). I saw the idea to use terminator legs, which I happened to have a pair so I went that way. The torso and shoulderpads are from the marine vehicle sprue, and I have no idea where the head came from.
The arms are the heavy bolter mounts from the Valkyrie kit. I plan on using one of the missile pods from the same kit as the main part of the thunderfire barrel, a razorback hatch as the base for the cannon and some extra old chimera tracks.
It's going to be work, and I need to put any more work off a week while I finish up the Imperial Fist commission, but so far, I like what I have..
After this, I have at least 2 major Ork projects in the works. Stay tuned!