I bought the ingredients and was trying to get the Coral Leggings made by a Bonecrafter that was recommended to me. She agreed, and I was happy to have 2 more STR for my macros.
Then an HQ happened out of nowhere. I was not expecting that in any way and I was totally dumbfounded. Don't remember the moon phase or day of the week, but I'd bet neither were optimal for an HQ. The crafter was 100 Bonecrafting and 60 Leatherworking.
All I know is that I have a ridiculously rare item in my gear set ^^
The HQ ones (Merman's) have been dated on AH sales in fairy since 2003. So they can't be new. Just no one makes them. Yet they are pretty decent for warriors.
I have made about 40 of these at lvl100 bonecraft / leather 60+1+3 (NQ results ofcourse, not HQ :p) which makes me believe the leather cap is higher than 53. Tried it again 20+ times with bone98/leather 62+1+3, and still haven't gotten a single HQ.