Very nice system you have put together. Until seeing them, I had forgot about those non-descending lowercase descenders. Fond memories. Idea: Since you are giving font options, perhaps also put in a choice for the all uppercase font of the actual Model 1 which was solely due to Radio Shack management skimping $1.50 by not including a second 2102 chip (128 bytes of static ram). They instead hackily remapped displaying characters 0x60-0x7f (lowercase) as 0x40-0x5f (uppercase) ... despite lowercase being in the system character ROM.
When you reboot into the "BIOS", are you corrupting the main 48K of RAM - or is it still intact? I was thinking a nice enhancement would be to have a "monitor" mode option in the BIOS where you could examine and modify RAM. Basically a simple "freezer" like they sold for other computers of that era.
