Problem with original Alpha is that accessing memory as anything other than aligned 32b or 64b words (yes, including bytes) counts as bit-twiddling because only load/store instructions that it has operate on these two word sizes.

I can't remember any other non-niche architecture with 8*2^n word size that shares this (mis-)feature. (I suspect that Cray 1 and it's derivates also share this, but that probably counts as niche architecture)