So I created *DNAV which is a proof of concept interactive (MODE7) experience at present. It reforms the traditional *DCAT output and allows the user to cursor over the folders and files and hit enter to drill into a folder or *DBOOT an SSD. Space will *CAT if you have a disc selected, pressing space again will relist the folder contents. It of course is limited by the 8.3 character file format that *DCAT uses. The attached SSD contains the command, which is a BASIC program in reality with some supporting assembler logic.
You need to be running MMFS2 and then just place the BOOT.SSD in your root or some other place (you will have to manually *DIN it if so). Shift boot it or just run *DNAV. Keep in mind there is no bounds checking (so smaller ish directories), nor error handling so keep your cursoring within the visual bounds of the listed files.
Feedback welcome - if nothing else I had fun writing/hacking it old school style on the machine itself with the help of *BE.
p.s. To progress this further it would be better to have an OSBYTE API in MMFS2 to get the catalogue information
, but hacking the DCAT output was also kinda fun! And more broadly the concept of "shell" experience for the Beeb is interesting, though surely done before? 