Looking through various blogs, I can already tell that some of you have already done exactly this. You get a set of models and paint each one a different scheme. Either you're building a collection, or you're just trying out different paint schemes, or you're planning on having a true rainbow of an army! You can do it with any faction, since they all have their own factions within them. Space Marine Chapters, Aeldari Craftworlds, Ork Clans...
For me, it's one of each Space Marine Chapter and Chaos Marine Legion!
I've got most of them base coated at the very least. One set of Tacticals and one set of Chaos Marines. For each model I tried to give them bits, poses, and weapons that reflected their Chapter/Legion. Here's a veritable rainbow of the Space Marine Chapters based and ready for the next stage:
Along with two of the Space Marines I finished a few years ago when I started this project. Black was supremely easy to do. It just looks good! Iron Hands and Raven Guard represent!
And here's the White Scars marine that I finished just today. White is a VERY challenging color, and I know I'll have similar difficulty with the Imperial Fists. Those two will probably be my weakest models, but oh well! I did my best!
Let me know what you guys think! More images incoming of the rest of the base-coated models!