You mention this briefly, but it's worth pointing out that the CM-2 (and, I believe, the CM-1 as well) was indeed a single-bit-at-a-time processor, but the word

You mention this briefly, but it's worth pointing out that the CM-2 (and, I believe, the CM-1 as well) was indeed a single-bit-at-a-time processor, but the word length was arbitrary, not 32 bits. You could, in *Lisp (and maybe the low-level calls that C* used, I didn't work with that enough to know) define pretty much any bit length you wanted, up to the number of bits on the processor. They later implemented a floating-point accelerator that worked with 32 of the 1-bit processors in "slice-wise" mode to do 32 (and possibly 64) bit arithmetic, where the word was spread across all 32 processors. The CM-5 used true 32-bit SPARC processors. Also, the CM-2 had up to 128k bits per processor, and you could have 64k of them in one CM-2.