Hey Megarat - this looks awesome, I am note even in the market for a HHKB but this makes me want to bid on it! 
Thanks! It's a sweet little setup ... if I was more of a collector I'd keep it around without question.
Question for you, is your home driver a Filco Zero with clicky complicated alps with dampers in it? Do the dampers help with white alps at all? Do you find any transposition errors as a result of your filco zero controller?
Yep, that's my daily driver for home and work. (One at each location.) I don't know if the dampeners "help" per se, but they do provide a different tactile sensation that I prefer. Specifically, the bump is a bit softer. You can tell that you're bottoming out on rubber rather than plastic/metal.
I put in a few words about transposition errors back on the two big threads about this, but summarized/updated: no, I believe that my keyboards don't have this problem. I typically type 80-100wpm and I've encountered similar problems with other boards (e.g., Tactile Pro 1), and sure, I sometimes get transposition typos, but I think they're all my own fault.
Note that my Filco boards started as XM, not Fukka, and it seems that most complaints have come from those with Fukka boards. I've always wondered if there's a connection.