There are a lot of leather armors already... but, this would be cool, perhaps only in leather armors, no hide or studded.
Shark hides are also incredibly sharp (depending on the type of shark) when rubbed against the... um.. scale like things. Some so sharp that rubbing against a swimming will remove a good deal of your skin. Not sure how that could be represented in the toolset...
But, Shark hide would be good RP for sea elves.
Idea: Maybe a shark hide line of armors could be made for padded armors, since there are no padded armors now. Sea elves would want something light and unrestrictive for swimming and they have a big dex to take advantage of.
-TV