I am not sure (didn't research it first) but, maybe, Toyo standards are "multi-purpose". You could use one of the 45D standards as an intermediate standard, two bellows... and have hella-long bellows extension!
Sent with Tapatalk. Please, forgive autocorrect and my fat fingers.
Definitely possible, but with the 45D the bellows are screwed to the standards and meant to be not "user replaceable". Nuts to that, I bought a bag-bellows for a 45G, took the endcaps off, and screwed it into the standards of my 45D. Worked perfectly until I bought a 45G and put the bag bellows back onto its frame to use on the 45G.
Also, if you've got a 45D and need more extension, just grab an extra standard & bellows from a 45G and put it on the front (or back) of the regular 45D, that works without ripping any glue or unscrewing anything. I've got 3 standards on my 45G, with 2 bellows I can do nice close-ups with my 600mm Apo-Tessar and 465mm Apo Ronar.
They do have so-called 'intermediate standards' which basically join 2 bellows together, but front/rear standards are easier to come by used these days (I bought a 45G front/rear standard from B+H used for $30 or something).
Of course now I've got a 45G I don't need the 45D anymore.
Speaking of which, if anyone missed out on the parts in this thread (sorry for hijacking), I'm parting out my old 45D similarly, when I get around to it after exams...
edit: Actually, now that I think about it, I do remember doing something similar. I had the front-standard and bellows of my old 45D attached, the rear of the bellows I put a 45G bellows frame on it. Then when I needed more reach on the 45G, I attached this extra bellows+standard to the front. But yeah, ditched doing that when I got my spare 45G frame.
