Thought I'd carry on this conversation with myself....
Since my last post, I've started using a TC Electronics RH450. My initial reasons for considering it alongside the Tone Hammer 500 and something from the Genz Benz range were the included frills (onboard tuner, compressor and TubeTone overdrive), which allow me to reduce even further the size of my rig and setup time -- I play with 2 acoustic guitarists who have no setup time to speak of. Trying before buying where I am is not an option for very many brands, and I was assisted in my search by TB in general and KJung in particular; his video playing a Mouse semi-acoustic bass guitar through the amp finally convinced me that I could have it all!
I find it to be a great amp for the CR4M -- the tone is (uber-subjective verbiage spoiler alert) "dark", "woody", "organic", against the Markbass' punch and clarity, and it brings me a step closer to an acoustic tone, helped considerably by the incredibly flexible EQ section (4 semi-parametric bands), and very conservative application of the compressor (3-"band", controlled by one dial) which at a few clicks brings up the G-string level without noticeably limiting the dynamics of the lower strings, and equally judicious use of the TubeTone, which gives the tone a bit more "depth" before it adds any real grit or grind (although it does this in spades at higher settings).
Certainly worth a try, in my view, although it's clearly not for everyone -- TC doesn't seem to get an awful lotta love on this side of TB.