The Apple 1 had a lot of unused space that could be filled with whatever you wanted, that was the beauty of the thing--a beauty that was lost to some small degree in the later Apples, which had a lot more structure to them. You just couldn't do as much to them without giving up compatibility. That's not much of a problem with the Apple 1..
So I started thinking about improving the video of the Apple I. Since the video stuff is being emulated using more modern hardware anyway, why not stick the ability to go overboard a bit into some memory space that isn't currently used and ... go overboard with the video? Some graphics techniques used by other 6502-based computers could be employed, as could some of the tricks of game consoles like the NES..
Then it hit me. We've already seen a few products that put a full, working NES on a single chip, right? One of them was quasi-legitimate (they didn't exactly ask Nintendo for permission, but the thing emulated the hardware, nothing more..) All of the others, of course, are CPLD type devices with a boatload of crappy bootleg ROMs burned in. For moral reasons, I refuse to acquire one of these latter types, but it got me to thinking.. The techniques used to recreate the parts of the Apple 1 that you just can't buy anymore could be used to recreate bits of the NES, the C64, and whatever else.
Anyone else considered a multisystem project? Even just the Apple 1 and Apple ][+ or so?