To build a Mac II-capable version of Mini vMac, you’ll need the Alpha source code. You’ll also need a working Mini vMac setup, as it uses a 68k Mac program to set up the source. Pretty much any basic setup and bootable disk will run this okay:
The build options I chose are:
-t larm -ccs -m II -hres 512 -vres 384 -depth 3 -mf 2 -magnify 1 -em-cpu 2 -mem 8M
I’ve chosen to swap the Ctrl key with the Command (⌘) key, as most non-Mac keyboards work better with this.
The build program will export a file out/minivmac-3.5.0-larm.tar that you can unpack into the full source code. It’s a really simple build, and fast, too.
Now you’ll need a Mac IIx ROM image (which I’m not supposed to help you find, but it’s an easy search) and OS image disks from the Mini vMac System Software page. Have fun!