Is that confirmed? I would like to start a DK on another realm as well. Are there any restrictions?

It's in the patch notes, the very first point on them, to be specific.
"Players may now create death knights on any realm once they reach level 55. "
They're only subject to normal restrictions (You can't create a Horde DK on a PVP server you have Alliance characters on, etc), otherwise, you're free to make a DK on any realm.

I'm excited about this as well. A while ago my mom transferred to another server with her main (traitor!) and keeps nagging me to level the 25 hunter alt I made there. Unfortunately the prospect of STV YET AGAIN is so very, very unappealing. Being able to start at 55 will be very nice.

Agreed completely. I have several friends on different servers that i've wanted to play with for a long time. Problem's always been that they are high level, and i'd have to roll from scratch to eventually play on the same level as them. Nice thing about the dk restrictions being lifted is that i'll only have to grind 55-80 instead of 1-80.

@Liquoid I'm really glad I don't raid with people like you.
Damage meters are for idiots.
You sound like you would prefer to be at the top dps meters and not down a boss, then to be in the middle of the meters and down the boss ;(