Is there a way to make a not-so-discreet hint towards a slight reward for a role-played capture or some-such scenario?
I am not sure I understand the question. You can offer bonus conditions that can be completed for extra credits. But they must be reasonable and in good taste.
But you cannot say: "You can only complete this bounty through RP." Roleplaying usually occurs, even with a /duel. If you want to post that you prefer a roleplayed conflict, that's fine but the hunter doesn't have to abide by that. But it would be listed with your bounty as a special note.