Short answer: Yes, it's in the tanner's wards that they should be sold.
Long answer: It's made by goldsmiths (like most bone products, if not all), it's pretty easy to do (goldsmith15). The problem is, not many goldsmiths15+ will bother gathering the mats to make them, especially since 2 bonechip + 2 soiled femurs + 11 wind shards is worth WAY more than the bonescales would.
11 wind shards @ 300 each = 3300
2 bone chips @ 36 each (NPC) = 72
2 soiled femurs @ 144 each (NPC) = 288 (Wards: 2 soiled femurs @ 1000 each = 2000)
How much do people pay for BoneScales? 3k on average.
Now, I don't think these kind of numbers are going to entice any goldsmith 20+ to make them and sell them in the tanner's wards (where they can't sell many of their products), so your best bet are goldsmith who are skilling up on them and who want to get most of their skilling up fees back. Sadly, most goldsmiths who stumble upon soiled femurs will turn each of them into bone armillas (goldsmith15 also) and make 800 gil at the NPC instead.
Your best bet is to find the mats, stack them to 12 or so, and have a goldsmith make you 6 bone scales so you're good for a while.
Or maybe wear some other armor if you can't make your own bone scales.
Edited, Jan 2nd 2011 7:44pm by Docent42
FFXIV: Cloe Delisle
Scholar, officer of the SWAGGER Free company, Sargatanas server.