Back in 2008, somebody asked about  a novel dealing with the Black Douglas. I was rereading old posts and it jogged my memory. Nigel Tranter wrote a novel entitled Black Douglas. Here is the Wikipedia entry for it:
“Black Douglas

First published in 1968

Set 1448–1452, during the reign of James II, the central character is William Douglas, 8th Earl of Douglas, who restored the power of the Earls of Douglas following the murder of the 6th earl. It ends with William’s murder at the hands of James II himself, in Stirling Castle. It makes some speculative claims about his allegedly disfunctional marriage with Margaret Douglas, Fair Maid of Galloway.”

Keep up the good work, and best wishes for 2013.

Greg Stewart