I have decided to learn the various systems and variations as they are and not modify the button boxes.
A unisonoric Garmon from Russia would be an adventure.
It was my idea too, long long ago. Sadly but one day I understand - too many different systems for me
If you like adventures, you must try bandoneon. It's all keys instrument, and every key has his own layout. When i learned A, D and G, I thought I had already learned to play bandoneon
But it is endless learning (now I feel free in C, D, E, F, G, A and Bb keys, others are for future
). 2 or 3 rows "diatonic" accordions was easy walk after this, Garmon - a little harder, but possible. My problems started with new "diatonic" boxes (club, non-club, different bass layouts with 2 row 12 basses or 3 row 16 basses), so i started "to club" non-club accordions, to change bass side systems to one for all, and final pass was C/C# system. When I got Soberano accordion with this layout I decided that it's too much for me, and decided to change system of this wonderful accordion.