I think this is a "devs know it" thing, but I searched the forums quick for Plane of Sky Quests and didn't come up with any posts of the like so here it is:
All Plane of Sky quests should be multi-questable.  Currently, none of them are.  I'd imagine this has something to do with the time consumption involved in rewriting...  14 x 6 = 84 quests. (Accounting for 6 per class.  Exceptions of 7 Mage and SK, and 4 Paladin)
But... It is a classic mechanic:
2005
	Quote:
	
	
		| I didn't address quests much here. Most of the quests in Sky are for outdated stuff - you can't even give away MQs to level 46s on. Mostly peeps just don't want that low stat garb. There are a few notable exceptions. | 
	
 2004
	Quote:
	
	
		| I would imagine so, but if you find a ranger who actually has the fine velvet cloak you can guarantee he won't sell you the MQ of it even if you offer 1 million plat. 90% self haste (with epic) is INSANE! Some may laugh, but think about putting a wurmslayer in your primary slot just to check out how fast the wurmy goes and buzzes through the mobs(and throw in that +3 dmg aug from NRo Wayfarer Camp just for kicks). | 
	
 2004
	Quote:
	
	
		| I got it and the Black Silk Cloak today. No Ranger there so I guess I will MQ it for someone... | 
	
 2003
	Quote:
	
	
		| Went to PoS the other night. SPiroc Feathers did NOT drop on the isle. Went to Horsey Isle, keeled KoS and 2 capes dropped. I got one for my epic and guildee grabbed another for MQ. He hurts when he hits.... Dropped 2 capes some Gem, and a rogue only No drop belt with haste on it. | 
	
 2002
	Quote:
	
	
		| The cape is nodrop, the other 2 are tradable. The whole quest can be MQ'd. | 
	
 
2001
	Quote:
	
	
		| I looted all 3 items while playing my cleric on a PoA raid. The Diaphonous Globe drops on Isle 3. The Pegasus hide on isle 4. Those 2 are tradeable. The Cloth Belt drops as a very rare off the Spiroc Lord on Isle 5. It is no drop. I ported my SK up to finish the quest later that evening. | 
	
 Etc.