Your idea of using the Stradella button side of a junk accordion is appealing because I only really need the feel of the buttons, they don’t need to actually do anything other than stay in place reliably as my fingers roam about,
Thanks for YOUR idea for a left hand practice aid! I might try to make one.
IF (and a big IF) you find a junk accordion with all the buttons still mechanically working (if you can press them down and they reliably come back up), you may be able to simply remove the bellows and then the read blocks from the bass side. If all the buttons are working it might be possible to just close up that side and use the buttons with the bass machine intact.
However, if some of the buttons do NOT move and return as designed there may be some nasty mechanical problem with the bass machine which you might be able to examine and fix. The bass machine is quite complex but from what I’ve seen I thing most of it might be removed and, if needed, springs added to the rods (pistons?) attached to the buttons. In the worst case, one might remove and reuse the button plate plate and perhaps the buttons to make a very compact and lightweight practice keyboard.
On most accordions removing the bellows is simply a matter of pulling out the pins (or in some cases screws) and prying off the bellows. Then you could remove the bass reed blocks.
There are some videos on YouTube with instructions, for example “How to dismantle & repair an accordion” by Ian J Cole.
Remember one thing: I’m a beginner at this, having only watched the accordion tech disassemble and inspect my accordion. (He was fantastic, explaining/teaching everything and letting me help) From my reading I understand that there are many variations in accordions so some details of disassembly may vary.
A far easier thing would be to find an accordion repair/tech person in your area and get them to dismantle a junk accordion, strip away everything not needed, and make a practice device for you.
As for a diagram, I use one. I found several online but in most the size and even the spacing was not right, OK for visual reference but not for finger placement. I ended up sketching my own, just the central section around the F-C-G buttons for now. I can’t use it by feel but can look and position my fingers, then go to the accordion. I suppose for the feel I could make small cardboard cutouts or make short plastic disks and glue them on the diagram. But a dummy with spring-loaded working buttons would be far better, though!
Others here may have better ideas. The accordion stand sounds nice. Even more-so if you have your butler put the accordion on the stand and position it where you need it (then go fetch a cup of coffee!)
A bummer about the clarinet and embouchure problem. I play trumpet/french horn & guitar, played around with cello and violin, and had one quickly aborted attempt at the flute, but never tried woodwinds. One grandson is working on the sax, though! (I did get both grandsons melodicas recently - good fun for all.)
JKJ