It's Memorial Day weekend, plus it's sometimes hard to find partners, although I 100% think that you're going about it in the right way to look for one. The maps with more than one person have a much higher success rate if the workload is reasonably distributed.
You just have to understand that even going into a partnership for a CC map is a fairly large committment, and I imagine that graphic artists would want to know just who they're committing to before saying yes. The War of the Roses is an interesting topic from my end, but without any more information it's also not a big selling point. So maybe try poking around the Foundry forums, comment on some maps (or rather keep doing so) and if you find an artist that's looking for a good idea, shoot them a PM about your idea.
-- Marshal Ney