I own an 800XL and recently purchased the SIO2SD card reader.
It's a fine piece of kit, it loads games individually and it loads game menus that were pre-recorded onto the supplied SD card.
I wish to create my own Turbo Disk style music menus. I want to choose the list particular games, customise the header and the backing music.
If it helps my 1050 drive was fitted with the Disk Doubler mod. The menus are multi coloured and the backing music was generally the same synthesised backing track.