Zaxon has developed some new Dragon floppy disk controllers ! If you are unfamiliar with Zaxon, he is very well known in the Spectrum scene and has even developed an entire new spectrum from scratch !
A few people, including myself, managed to talk him in to making a controller for the Dragon and he has delivered. From concept to retail in under a month !
One of the nicest features that he has included is a 4 bank, selectable ROM, so you can have 4 different versions of DDOS (or others)
I have ordered mine already and though I would share.
Please note that I am not affiliated with Zaxon, so any questions should be directed to him directly
Another note is that his english is not great but it's understandablehttp://www.sellmyretro.com/offer/details/10652