Well...
Ser Vardis Egen fought Bronn over Tyrion's guilt in Jon Arryn's murder.
Ser Gregor Clegane fought Prince Oberyn Martell over Tyrion's guilt in King Joffrey's murder.
Dunk, a green apple Fossoway, a Targ (I think), and four other men fought in a seven man melee against royal Targs and the Kingsguard in the first Dunk 'n Egg.
Sry, I don't even know what the Rogue Prince or the Princess and the Queen are.
In the main story?!?! Doh!!! I need to go reboot my brain.
well... not sure if it counts, but Lord Rickard Stark died in a "Trial by combat" though King Aerys cheated and chose fire as his champion.
And the Hound fought in another one versus R'hllor, whose champion was Beric Dondarrion.