Not the usual Magic Jar question...

[CrimsonBukake]

I know a lot of people ask about trying to steal a body permanently and with certain DMs it may be possible. However I was thinking it would be cool if I could remain in the jar permanently and become sort of a cursed artifact. Or a multi generational ruler of a kingdom.

[Nettlekid]

Do you still want to be able to come out and possess people, or do you just want your consciousness to stay inside the gem?

I think an intelligent item might be the best way to get what you're looking for. Either start out as having your PC be an intelligent item, possess one forever at level 30 using the Artifact Lord Epic Destiny (http://lonelygm.blogspot.com/2011/02/epic-destinies-for-d-35pathfinder.html) (a little overzealous for what you're planning I think), or (I think this is the best way) have your PC be subject to Nybor's Psychic Imprint (http://www.wizards.com/default.asp?x=dnd/mb/20041215a), and then have the real PC die. The way it works, all your memories and personality are copied into a crystal while your mental ability scores are drained to zero, and if the crystal is made into a magic item then it becomes an intelligent item with basically your mind. Once that happens just add on costs for at will Telekinesis (if you want to move, or maybe Unseen Servant for cheaper if less stylish transportation) and either Dominate Person or Magic Jar, depending on how you want to do it.

[CrimsonBukake]

The idea was to basically transfer your soul to the jar permanently while retaining the ability to reach out a gank somebody. I originally thought this possible via permanency, but I've been told otherwise.

[Drachasor]

The idea was to basically transfer your soul to the jar permanently while retaining the ability to reach out a gank somebody. I originally thought this possible via permanency, but I've been told otherwise.

It is possible via permanency if the DM allows it. Similarly, it is possible via making a magical item if the DM allows it.

Personally, if I was asking the DM to allow crazy stuff like that, I'd be more focused on becoming a sentient demi-plane (or construct-sized planet, but I think the demi-plane bit is more likely). That's just me though.