there was a talk of creating a machine with all programmable chips back in the day... something on the line off, you want NES? you throw in a disc, it programs the chips for the session as the NES one, you want snes, or amiga? all the same... you would just have to feed the rom/games/homebrew/whatever. it wouldn't be an emulation even since the chip would act 100% as the real thing. sadly i forgot were i read this topic....
That is a great spec you have there, a few ideas I have had Add a flash rom (paged in during power up and hard reset) containing bios to initialize the system devices, pc keyboard and mouse drivers, dos to access the sd card and possibly a gui desktop The Z180 MMU does handle 1MByte of banked ram but it might be an idea to add an external banking latch allowing the top of the memory map to be banked for a larger ram size to be accessed (thinking that your twin dac'd sampled sound is going to use a lot of ram). A 16bit latch tied to a 16K banked area would allow 65536 pages of 16K and give access to 1GByte of ram (ok maybe only 13 bits would be enough as this would allow 128MBytes of dram to be used, I dont think that we really need 1GByte of dram on a console LOL!) This will be? a very nice system indeed