I hear ya man. AFAIK, NCM doesn't offer the early JMI type fawn, only the Rose Morris era fawn. Music ground is the only source of JMI style fawn that I know of, but have never had any dealings w/ them. There's actually two different kinds of this newer JMI style fawn that I've seen. One is kind of shiny and one is matte. I prefer the latter, but both are fairly close to the original stuff.
I build a 3 channel AC-30 style chassis that fits the NCM cases. It's not an exact clone, so the control panel is a bit different. Weber's 6v30 chassis will fit the NCM cases as well, but the upper panel controls are a bit cramped because it's a copy of the later integral TopBoost AC-30. But that doesn't mean you have to use all the holes. A homemade panel overlay will cover up what you don't want.
I bought a friend's Vox Essex Bass amp complete with chrome cart to use as my guitar amp with my '63 Gretsch Corvette single pick up back in '69 or thereabouts. Back then I had no idea how it sounded. I just knew it was louder than my older Gretsch amp, it looked cool, and said Vox. What more could one desire?