Sir John has been investigating adding a solution to Quenton’s murder in his Nitpicker’s Delight patch for Ultima 6:

The Quenton murder not being solvable was always nagging me. The somewhat inconsistent clues in the game as to who is the culprit didn’t make it any better – but from all bugs there are: this was the most obivious and the most obnoxious for me.

Well, it might be a far stretch, but I may have found a way to make the murder of Quenton solvable in the original game after all.

I have been fiddling around with cheats and the code in my spare time and tested various approaches to set flags where they had been forgotten.
(“Setting flags” in this context can only mean: an in-game way to check for a certain status, of course.)

This led me to checking for items being there or not, i.e. the Seance spell in order to trigger another (not yet existing) block of conversation with Quenton if the Avatar was to talk to him after casting the spell.

…

My tests so far are prpomising (otherwise I wouldn’t post about it ;-))
1. I can check for the Seance spell being present (item 58 quality 72) easily. It can be either be the scroll itself as well as the spell inscribed in the magic book.
2. I can check the required reagents and substract them from the inventory if the player decides to cast the spell
3. I can check for the players magic level, but I have to figure out the code yet

What I will never be able to achive is to make use the regular spellcast method. Casting Seance regularily simply does not set the in-game flag required – which is why the bug is said to be unsolvable.

But I do think I have come up with a workaround that is good enough so one can enjoy it.

Indeed, he has even begun planning how to implement his workaround.

Now, having read Sir John’s plans, I think he’s got a rather excellent solution lined up, one that will — fittingly — offer multiple outcomes (e.g. Michael will attack the Avatar and have to be killed if confronted, or carted off to the jail in Yew if the Avatar brings the matter to Lenora). Indeed, his proposed solution is very like the way the Ultima 6 Project handled the matter.

But, Sir John would still like any input that Ultima fans have to offer. So if you have any thoughts to share, head on over to his site and speak your mind.