I kinda like the idea. I'm a horribly slow pixeller, and I could see exercises like this helping one to find ways to streamline the process and even ditch habits like applying AA in the middle of shading that'll end up being erased come time to apply selout, or when the shadows are tweaked. When I finish some of the stuff I'm working on right now, I think I'll give this kind of stuff a try. Not going to post them or anything, just trying it as a learning exercise.
I've got a question for you too, are these versions you're posting now the only attempts, or do you find yourself making a couple versions of the lineart and the colourjobs before you end up with one that you like?