Raising for visibility as unlikely to be space for any new features in the core on the DE-10 nano due to space limitations, and this is very niche.

The localisation patch for Densha De Go! adds additional features (like Transfer Pak support), and one of them is if you use the hack on a real N64 that has a 64DD attached then the game displays a different intro. I am unsure if any other hacks do something similar at the time of writing.

https://www.romhacking.net/translations/2947/

It would be fun if it were possible to set 64DD Connected/Disconnected in the OSD and whatever flags/conditions are are being used to detect this in the hack are met to set the intro.