Obscure Microbee Hardware Enhancements

[MbeeTech]

There is a full speed SPI compatible interface for the microbee that was originally designed and made in the mid 1980's as a mouse interface.
It is connected using the 50 way expansion interface.
These days it is a very useful way of attaching modern SPI peripherals and MMC/SDCards to a microbee to make experimenting with a microbee easy and fun.
Driving SPI peripherals can be easily accomplished with just a few simple MWBASIC IN and OUT statements so who needs a Arduino Sketch when it can be done with microbee?

Hello Someone.

I'm sure this would be handy & a bit of fun to add.
Would you be able to put together a rough schematic & port map?

Thanks!