As far as other unique things, I'm pulling for new skin tones and eye marks like you see on many NPC Human Necromancers and Death Knights, but there has not been anything said about that one way or another.
On the subject of racials, Death Knights currently use their race's racials, and there's no indication that will change. Arcane Torrent has even been adjusted to grant runic power.
And here's one last Death Knight question from krat: Do all abilities that require runic power drain all of it, and if so, do they actually scale with the amount of runic power one has?
Actually, krat, Most runic power abilities simply take a set amount of runic power. Those that do take all of your runic power, such as Summon Gargoyle and Unholy Blight, do scale in some way, even if it's only lasting longer based on how much runic power you have.
jurandr asks: We know they're getting rid of the Amani War Bear mount. Will any of the other BC mounts be affected?
No, we'll still be able to get all of the other mounts that currently drop in game, so once you hit level 80, feel free to go try to solo Bloodlord Mandokir for that raptor. The Amani War Bear was specifically removed because it requires a precision timed event that requires skill and discipline at 70, but will be trivial at 80. Luckily, we will have replacement bear mounts.
Joene asks: Are factions implemented yet?
Not completely. Each of the starting harbors in Northrend has a faction, and there's also the Argent Crusade which was discuss in a previous AABT. The Wolvar and the Oracles can now be quested with in Sholazar Basin as well. However, for the most part, factional rewards aren't really in, and we'll probably have to wait a few more patches to get full implementation.
Aryc Ogre asked: What I want to know is... do the walrus-people have a quest for you to retrieve their stolen bucket?
I have not seen one. However, I actually agitated for this back when we first heard about the Tuskarr, and I think I'll go throw this up on the Beta suggestion board right now. The legacy of the bukkit must live on!
That's all I have time for for today, but please do continue to ask your questions in the comments. If you haven't seen yours answered in a few posts, ask it again. The plan is to do this daily until all your questions are answered or Beta testing is finished!