Really, really nice work!

If any of your friends are doing Orks for the period, maybe look into seeing if you can find a copy of the Angels of Vengeance campaign pack? It's Dark Angels* vs Orks. It was re-released again as free download for later editions too, but the original 2E one was pretty good for changing up scenarios from the usual ones most people played, and the missions "accelerate" gradually; so, if you each paint up what you need for the next mission you play, you should end up with two fairly comprehensive armies for the game. It's probably also a nice excuse to make up some bits of terrain too, if you like. Also, you don't need totally new units for each mission, as quite a few missions re-use forces and/or characters that survived previous missions, so that keeps the painting queue more reasonable. Anyway, just an idea.
*Other Space Marine Chapters are available! 