Not entirely sure about Dragonscale or Tribal Leather, but the Elemental Leather can go for a pretty copper or five.
When I do see them on the Auction House, the Fire Resist patterns attained from the Thorium Brotherhood at Honored (Lava Belt and Molten Helm) for from 250g to 550g each.
I am honored with Thorium Brotherhood, and a 300 Elemental Leatherworker. The problem with those two listed patterns is that they require Lava and Fiery Cores, things that can run up to 55g per, at least on my realm, Mannoroth(Alliance). One of those two patterns requires Core Leather also... so the overall crafting cost comes out to about 300g. If you sold one of these for, say, 400 gold, that's a 33% profit.
Just as well, I have been approached by a Raid Group on their way to Molten Core, and later ended up with several hundred gold in tips for all the work I did. And THEY brought their own materials.
So needless to say, you CAN make a good bit money in Leatherworking. But, from my perspective, the money's in Elemental, for the Fire Resist gear.