Forget some modern up to date thing that has to emulate older stuff! Somebody needs to re-tool the A1200 and start churning out fresh machines.
Then the cost has to be right! None of this bespoke £500+ stuff that prohibits everyone except the diehard fans.
Escom did it with the remains of whatever Commodore had at the time. Do this again, A brand new fresh A1200 that just works with all the old kit knocking about.
Jens did it with the C64 board.. I know it costs a bomb but it can be done!
But in reallity I know it is all a pipedream. So I have all my old Amiga's still knocking about. I get them recapped as needed, tidy things up etc. They will serve there purpose until I am too old to use them.
The Amiga brand is dead! But the memories and spirit are not