Adding a USB-serial adaptor could be a good idea, once we get the core code working we could always add USB hub support, that would give you lots of serial ports (although the first hub would need to be self powered, as there is no way the cable will put out 500mA).

Keyboards would be doable in boot mode, but I don't fancy writing the whole HID class as a first step.

As for the flash card reader, I think they use mass storage class, so adding this may give us the CD-ROM and hard disk support too.

So the new list is:
1- USB-serial adaper
2- CD-ROM (and HD and flash maybe)
3- Keyboards

Mark
20GB MKII 090000916