We've never seen this one before, but then again, we've never seen a loot item as complicated as that Ethereal Soul-trader before. Blizzard wants to test those new Upper Deck loot items on the PTR, so if you go Landro Longshot in Booty Bay on the test realm only, you can input special test codes for each of the new items: 1111 for the Path of Illidan item, 2222 for the D.I.S.C.O. ball, and 3333 for the one everyone wants: the Ethereal Soul-trader.
The only news coming off of the PTR is that the disco ball object still has the placeholder tag on it ("[PH] Disco ball"), which means the name might be a little more formalized when it actually appears on the live realms. But this testing might answer one of the more pressing questions we've got about the Soul-trader -- we already know that any player (not just the one who summoned it) can exchange the "Etherium" currency that you use to buy items off of the vendor, but does that mean that any players who kill mobs that give experience or honor near the trader can gain currency, or only the person who summoned?
We'd assume that everyone can do it -- in that sense, getting this card is really like opening up a special vendor rather than just getting all the trader's items for yourself. And there's one more bit of news we can take from this: since these cards are going into stores on July 1st, we'll very likely see patch 2.4.3 on the live realms before then. To the PTR!