Yes, the Arthurian legends are a bit of a cliche, especially on the surface (the sword in the stone, Merlin etc.) but there's a massive amount of material in the medieval literature (and even in Tennyson and Roger Lancelyn-Green's rewriting of the stories for kids in the 50s) that tends to get overlooked. Chaosium's Pendragon went at this with a vengeance and captured the feel of the stories very well (at one point it was reviewed as the best RPG because the characters were so deep). It assigned character traits based on the seven vices and seven virtues which then played off against each other and used these to give quests moral solutions where a player's character had to struggle against their own personal weaknesses. It also had a dynastic component, you had to raise a family and at the end of the whole cycle you were playing your own grandchild. The game was never a commercial success as it was too far away from standard RPGs and seems to have disappeared completely (White Wolf picked it up around about 2005 but it's not in their catalogue). The Paradox game Crusader Kings has lifted the dynasty element and character traits from the game but that's about country management in real medieval Europe. Combining the Avernum game engine with the Arthur stories Pendragon style would be (for me) a killer game. You can have the Matter of Britain playing out in the background, and then knights wandering the lands either looking for adventure or going off on major quests for the Questing Beast or the Grail. One problem is that the adventures in the stories always tended to be singletons. You also have a few pitched battles/sieges towards the end and I'm not sure how this would work with my limited knowledge of Avernum.