Hello there!
A friend and I have been trying to acquire the tailoring pattern mentioned in the thread's title for a while now. We realize the dropchance on this particular item is incredibly low, but despite this and the fact information on the pattern in question is scarce to say the least, we're still quite determined to get it.
To that end, I was wondering if there are any people around who might have more information than what Blizzard's officially published loottable might suggest. So far, we've managed to get a hold of a Game Master who's confirmed it to drop from the seahorses mentioned on that page. He was also kind enough to double check the bug database incase any bugs on the matter were reported which, fortunately so, didn't seem to be the case.
If there is anyone out there who might have more in-depth information, and is willing to share it, we would greatly appreciate it.