I came across this thread and thought one of my own might be of interest to you- a bit more achievable than doing scratch built stuff!
https://www.dpreview.com/forums/thread/4605882
"+10 to 4 'achromatic' close up diopter from telephoto zoom, in typical filter thread"
Basically, off the shelf achromatic (or better), multicoated positive-power 'groups' from telephoto zooms for 35mm cameras. Glass diameters 45-60mm+, focal lengths 80-220mm+. Sometimes just a thick doublet, sometimes a doublet surrounded by elements, sometimes a doublet with a singlet infront of it (slight meniscus, plano convex).
The focal lengths of these elements I described might make them abit better for medium format, but that's because I don't have many to hand- another source is those 300mm f6.3, 500mm f8 "wundertute" refractors..
So, you could atleast make an achromatic 'landscape' lens, or some simple "symmetrical achromats".
I would absolutely not go as far to say as you're making an equivalent to a computed Rapid Rectilinear, because quite literally saying they're both made of symmetrical achromats is saying... nothing, really- they're completely different in design.
But don't be discouraged, much fun to be had. I'm sure weaker elements can be found.
Bundles of vintage zooms can be had very affordably, you may need some tools to get the elements out (rubber bung, JIS screws, small flatheads) but worth your time in the long run. Easier when it's "one way"...
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