"Kahless", by Michael J. Friedman, is at least on my top ten favorite Trek books, at least the part based in the past, Klingons are by far my favorite enemies in Trek, and my second favorite movie is Undiscovered Country, because it's so Klingon-heavy.
So I would definitely watch a Klingon epic.
However, the Klingons were kind of exhausted in the TOS movies, so the chances of a Klingon epic making it big would be slim.
And if they were going to make another Trek movie, I would prefer it to be about J.J.-verse, to make it a trilogy. Klingons just aren't popular enough, and Trek hasn't become mainstream enough for a full-out Trek-nerd movie to work...