I wonder... If the Powers-That-Be have the ability to design siege in such a way that toons from different servers can co-exist, why can't they create a brand new server and allow people to move to the new server. This would be a special server that new toons cannot be created on for the first month or so to prevent people from "camping" names.
Then it would be a first-come, first-serve situation where a player selects the toon they want to move to the new server.
Once the registration has been processed, a message will inform the toon that they need to go to their house and a button will appear like the "Enter Siege" button... call it "Move to New Server"
When you click that button, the toon is then moved to an intermediary zone and all data gets copied to the new server.
If a previously moved toon's name conflicts, then the toon is temporarily renamed: Server_Name ( ie, Reni_Twerp )
Unless a toon is a guild leader, they will be un-guilded to make it easier to just get into the server
When all the data has been copied over, the toon is tp'd to their house in the new server.
Now, guilds... we don't want to lose all of our resources here, so when a guild leader makes the transfer request, there's a little more work that needs to be done.
The guild leader must inform everyone that the guild will be disbanded on the old server when they accept the transfer to the new server
The guild leader receives the same treatment, but retains guild information and guild data is copied over to the new server
If a previously moved guild has the same guild name, the new guild name will be SERVER_Guild Name ( ie Reni_Sexton )
Once the data has been copied, the guild leader is then sent to his/her house
Exclusively on the new server will be an npc that allows SERVER_ named toons/guild leaders change temp names to something else. The new names cannot be previously used names.
A system as described above could allow for a successful server merge into a brand new server that would make for very little downtime.
My main point is that currently, the siege server copies player data pretty successfully.