Throw in a little hypo and that's a smoking animal. Or maybe a hypo pewter? Or hypo super pastel? I'd go for pretty much any hypo co-dom animal and then just pick your favorite of them. You can't really make a "wrong" choice here IMO. REally just whatever is your fancy.
If you don't mind me asking, why co-dom and not just dom? (sorry if that's an incredibly basic/dumb question)