Making a rally dash frame

If you aren't inclined to weld on your dash, look into a Permatex product called "High Temp Metal Filler" (available at some auto parts stores, but I get mine from Caswell's Plating online). Originally formulated for exhaust leaks, it's good to 2000 degrees -- perfect for powder coating -- and is grindable, sandable, and very easy to work with. It's a bit pricey though (I pay $12 for a little blister tube).

Good luck with the repairs!