Here is an idea for a NEW jail. I got this idea from Morrowind. Lets have a city, one that is similar to Vivic city. And above it, there is a floating meteor (which is what you find above the vivic temple). If you get sent to jail, you can either choose to stay there a certain amount of time in a cell, or you can work in the slave mines (the meteor) to pay for bail. Inside the meteor, you only have a pickaxe that cannot be used to attack players, only to mine to pay for bail. Admin can set the bail (say 1 million to 5 million) And the player must mine for long amounts of time, then go to a small shop that buys gems to sell them. Once the player has mined enough to pay for bail (the shopkeeper keeps track of your bail money) You are free to go.
Also, how about some serious punishment for repeat offenders. If they do something seriously wrong and are sent to the cells, how bout making them prison unsavory womanes? Spawn a big burly man behind the player, and the player gradually loses health. The bot keeps yelling "Keep Still" like the travellers and elves.