How about this':
When an AFK person is KOd, they cannot be murdered. Their body lies on the ground until they would stand up, then logs itself off.
If a person is summoned with a murder clue, it works the same as it does now.
This way, Theft will be punishable by a beating and a return theft. If someone were really angry, they could repeat with enough clues to actually permakill a thief, but that would be time-intensive unless the thief left a carpet of clues. Also, this would make grievous damage more important.
We would see a shift to a three-tier justice system -- lowest is simple location of Hfire, then a beating, and inventory theft with POSSIBLE death, and at the highest level, offline permakill.
What do you guys think?