I was recently pondering the whereabouts of the Dust Bunny in Legion's Dalaran, and it looks like someone has found its hiding spot!
Anne Stickney of Blizzard Watch happened upon the Dust Bunny while testing on Alpha. You can read more about her discovery in this article written by Liopleurodonic.
With news of the Dust Bunny's discovery, I had to go and check it out too.
Upon entering the Barber Shop in (new) Dalaran, there was a Dusty Rug (Wowhead object link not yet available) waiting. Clicking on it removed the rug to reveal a wild Dust Bunny.
You can see the paw print icon pop up on the mini-map if someone else "summons" it.
It was a close battle, not having any max level battle pets on Alpha, but I managed to secure my own poor quality bunny. It spawned in as a level 25 solo wild pet; capturing it brought it down to level 23.
Much of the room is considered obstructed, but I did find some sweet spots. You'll be able to battle the bunny if you stand at the stop of the stairs or in between the first two barber chairs. It's strange since most of the room is clear and flat space, but *shrug*.
Curious if I could capture another, I waited the roughly 15 minute respawn timer and clicked on the rug again. This time the bunny spawned in as uncommon quality.
Good news is that yes, you can collect the maximum number of Dust Bunnies allowed in the Pet Journal. This being a wild pet and all, it only makes sense.
The bad news... it's a wild pet, so it CAN be killed by player attacks. I actually found this out on accident, while I was messing around with my hunter's attacks. Oops, sorry little one. :(
Perhaps this specific pet, being uniquely spawned and a SINGLE spawn, should be immune to player abilities/attacks. Otherwise, I could imagine it very easy to grief someone attempting to collect their own Dust Bunny.
Speaking of others collecting this odd critter -- if you summon the bunny but don't engage in battle or capture it, someone else can come along and battle/capture it instead. Or it can just happily sit there until it despawns. I didn't stick around long enough to see how long it took for the rug to reset and despawn the wild Dust Bunny, but I'm guessing it's the same amount of time as the rug's respawn timer.
Summoning your Dust Bunny will generate a puff of dust, with the pet's little nose sticking out. Adorable (and sneeze-inducing) or what? Really looking forward to collecting this pet once Legion goes live! :)