Is a cleric in deacon's orders, who is appointed an honorary Canon of a Cathedral Church, entitled to wear a cassock with the same colour buttons and piping as if they were a presbyteral Canon? Personally, I can't see why not. And I bet there are precedents. For example, back in the ample days when young men of aristocratic family took Minor Orders so as to qualify themselves to hold lucrative benefices, without any intention of proceding to the subdiaconate with its obligation of celibacy, I bet there were some of them who held canonries. (Memories here of Gregory Dix's characteristically catty demonstration of the fact that medieval corruption survived more happily in the Protestant denominations than among Catholics: a young Hannoverian princeling was "elected bishop of Osnabruck" only a few months after his birth, enjoyed the revenues of the see all his life, and was addressed as "Right Reverend", without ever embarking on a remotely ecclesistical career.) Information, please. There might even be eighteenth century portraits settling the question. And, please, no cracks about how we ought to have more dignity than to accept baubles from That Lot. And don't correct my spelling of Hannoverian.
If everybody floods in with comments and suggestions, this Blog will probably, in a day or two, hit its 100,000th page view since it was founded on the Sollemnity of the Immaculate Conception in 2007. A Thank You to all who have continued to tap in, even when they found me irritating. And the biggest of Thank Yous to the Blog's Technical Officer, Mr John Hanks, whose middle name is sine qua non and who, if he were in Holy Orders (perhaps the Apostolic Administrator will tonsure him?) would deserve to have a cassock with gold piping. And don't correct my spelling of Sollemnity.