well, you can copy files to the sd card with the reader, the 7000 just will not see them in the screen. This is because the text in the kn7000mn.inf file has not been updated. If you manually update the text with a hex editor in the correct data blocks, it works fine.
Therefore it should be possible to make a program to transfer to the card on the pc, similar to the old ttx file manager, which updates the text, and even gives you the opportunity to rename the 6 character floppy format names to the longer 16 characters the sd card can usefully accomodate.
The problem might be if users try to copy files on the card reader that the 7000 cannot read, the program might need to certify that any technics files are 7000 format, or at least readable by 7000. Midis should be fine, also pictures.