Today in huntering news, I've tamed Jadefang! Wahoo! Jadefang is a rare spawn Shale Spider from Deepholm. Shale Spiders are a must have for any hunter who's goal is a stable full of raid buffs. With your rocky buddy at your side there's no need for Mark of the Wild (druid) or Blessing of Kings (paladin) because your pet get give an equivilent buff called Embrace of the Shale Spider. He can also web, much like the regular spiders, so he's neat for PvP as well as PvE.
Jadefang is tough to find in part because hunters and non-combat pet collectors want him (killing him always drops the companion, the Tiny Shale Spider) and in part because he's a little tough to get to. The only way I've found to actually get up to him is with the daily quest Underground Economy. This is a Therazane reputation daily, so for the most part you will need to complete Deepholm up to these dailies. I've heard engineers can get up there without it, but if you're not an engineer you'll need the daily. Disengage doesn't go far enough, I've tried.
Once you have Underground Economy run though the tunnels and two the main room with the white blocks. In this room take the right tunnel, then hug left. If you've done the Therazane dailies before you're heading for the ledge Pebble is on. Once you're at the ledge, look to the right and you'll see another ledge with no other access points. Once you see this, turn around so your back is facing this ledge, place the bomb you were given by the quest, Ricket's Tickers and wait. When the bomb goes off you should be thrown to the otherwise inaccessible ledge. From here simply run to the back of the short tunnel. If Jadefang is not there he simply has not spawned yet. You can either wait (I did this myself and got him after about 6 hours. I killed him for the non-combat pet) or you can check back each time you do this daily (I also did this to tame him).