Great cdp's with analog volume control?

My list so far is-

Audio Aero Capitole
Resolution Audio Opus 21
Musical Fidelity CD-Pre 24
Krell KPS-20 - not sure of that model number

Anything else of note? Also, do people think there's anything to be said for having a dedicated pre-amp when using one of these cdp's as your ONLY source?

Thanks!

P.S. Sorry for any weird formatting, I'm writing this from my handheld!