Yes... I would love more stable slots, IMO, they should add two more in the next expansion really (although I voted for 6 more

) The pets I currectly have are:
Ghostwolf: My ghostly wolf tamed in TBC, was the hardest to tame from all of my pets, and my favourite; it being a wolf also makes him my dps pet for raids

Due to my latency, the drums, heroism, and meta gem weren't enough for me to tame it, I needed to obtain Juju Flurry...and wreck my Bloodsail rep. And it still took me a few more tries to get it tamed.
iKrush: The first King Krush I spotted, I didn't have the preperations to tame him but tried anyway, I got killed and then a druid from the other faction killed him as I ressed

The 2nd I spotted was already dead, and I killed the 3rd as I wasn't BM (found him by chance, was before Dual Spec.) The 4th was killed by another druid FROM THE SAME FACTION, while I was taming...and I had him tagged, lol. Tamed on the 5th I found, was really late, and I paid 2 people to keep him tagged while I res/tame another beast to abandon and then tame King Krush. Though it took me more time to tame that Ghostwolf, I still rank Ghostwolf as a harder tame.
Flubber: The slime from the Oracles daily, my tank pet. It tanks normal lvl 80 instances and below, MC, Kara 1st boss, and ZG raptor boss
Spirit Beast: After spending 2 weeks searching for Loque'nahak and not even seeing its corpse I chose to tame it at a later time (even after Gondria got released.) I preferred it because it is also killed for an achievement and others would want to tame it too, makes it more challenging

I was leveling up a raptor this once, then I saw Loque (without looking for it, lol) and so I abandoned the raptor and tamed Loque
The Beast: Patch 3.3 made all my rare spawns no longer display their (Elite) status, and then I heard of The Beast on this forums yesterday, I knew that I had to tame it; and so I abandoned my rare spawn Terror Spinner. Unfortunately for me, I got hacked 5 days ago and was just left with my pvp gear(will get all my equipment and gold in 2 weeks said the GM.) I ended up regemming and enchanting to + haste, and the usual food, elixir, and speed pot buffs to tame it. After many unsuccessful tries, I finally got it tamed on the 51st try, lol. I noticed that the beast charges every 5 secs or so, rarely does he not (I'm not 100% sure, but I think when he doesn't it is because he misses) so I had to get him to miss twice or w/e (my tame spell was 15secs with all buffs and enchants.) While an extremely difficult tame, I will have to rank him just below King Krush in terms of difficulty of taming/obtaining.