It looks like this has changed, as Turbine recently posted an update to its paid premium services forum thread. In it, the studio announced that all such transfer restrictions are removed:
We are also happy to announce that NA World Character Transfers are now available for transfer between ALL North American servers as of 9th November, 2011! Yes, you may now transfer TO Brandywine, Crickhollow, Dwarrowdelf, Elendilmir, Imladris, Landroval, or Riddermark!European players have access to this service as well.
Unfortunately, these transfers aren't free but come with a hefty pricetag. Players looking to move server homes will need to shell out either $24.95, €21.95, or 2995 Turbine Points. There is also an issue with moving a character back to a server that it came from, so players cannot do that until Turbine resolves the issue.