For Shay I could DEF see a professional relationship and possibly, we can discuss it with whoever Shay's owner is down the road as a plot possibly exchange of ownership, depending on how much Duncan believes and synphazises with her story? Especially if he can't convince/get her freedom. That could be the next best thing.
I'm a huge fan of crack ships and would LOVE something complex and emotional and gritty and confusing and blurred lines and ugh perf with Mads. They are different--so different---but as i mentioned above, Duncan has a dark side too.
Ronan Could be interesting too. Duncan is a pro rights person but isn't at the point of "lets get rid of the system", but he could be swayed and i'm all about character development, organic development and seeing where it goes. But that could be something we explore.
Patrick since he his related to Nicholas would probably be on good and friendly terms with Duncan, since Duncan is on good terms with his brother?