I don't think it's worth greening, because it obviously isn't happening anytime soon, but I'm curious about whether Toady's going to expand the "site claims" idea to personal property.
Right now it's clear that the system is limited to land. However, it sounds like a pretty flexible system, and I wonder how hard it would be to port over. So that, for instance, muggers could end up holding a "claim" on the coins in your pocket, and assault you for them.
It just seems like it would be possible to do, and it would add a lot of fun and excitement to adventure mode, and also end up making for a lot of theft, bad blood, and general fun in Fortress mode.
You could even add a sort of rudimentary bona fide purchaser system without much difficulty. Thus, if a thug beats you up (nonlethally, with the new system), and steals your gold or your blade, then under all non-goblin civilizations your claim would be better than his, and you could reclaim your property without violence against you from groups unaffiliated with the thug. However, if he resold your sword to a weapons shop, or used the cash he stole to buy food, then the merchant's claim would take precedence over yours (and obviously over the thug's), because the merchant is a bona fide purchaser for value. All you'd need is a claim priority system (that could even be modifiable!).
A claim priority system could also make for more diversified civilizations even without getting into land-use law. For example, goblin civilizations could basically have the strongest able to lay claim on whatever they want. Despotic human civilizations could have it so that higher ranking humans can lay claims on any property owned by a lower caste. Elves could not really have much of a claims system at all. Dwarves could have a super complicated system with lots of usury, loans of property (a claim limited in time), and interests secured on personal property (e.g. "I'll give you food today, but if you don't pay me back in a month I get your sword").
Anyway, obviously only artifacts would keep track of a ton of claims on any given item (which would in turn facilitate fun wars over artifacts), but during play it seems like it would be possible to keep some claims on some important items (e.g. anything the adventurer owns or tries to steal, or in dwarf mode property that has been claimed as personal property by a dwarf, since most property isn't claimed, so the system wouldn't be too resource-intensive hopefully, particularly if the claim just became a property of the time for a time).
Welp, that was longer than I intended. Ah well.