CJ Classic is definitely on the warmer and darker end of the spectrum. If you want rich and organic but not dark try Audio Note.
What are the more subtle sounding tube preamps?
I mean "subtle" as in relatively less tube saturation or color than your average tube-pre. Common sense tells me less tubes as in a single dual-triode, but in reality that may not be the case. I currently have my eye on a CJ Classic. Not sure if that will fit the bill. Any suggestions welcome.