If you have the Bernoulli disk cartridge interface board, look at that. I'm *not* stating it's a functional ide interface, just that it's so simple, and in that sense resembles a generic ide card. The 80186 does have a 16 bit data bus remember. That alone likely ialleviates the additional logic needed to implement an ide interface.
And I'll have to modify the poll
Dual floppy vs. single floppy + likely dead 20mb.