In the first 10.1.7 PTR build, Blizzard has added four new mounts consisting of two new Infernals, a giant Murloc, and the Azure Worldchiller Dragon.
We have models for the Infernals and will update the models for the other two when we find them.
Infernals
These new Infernals appear to be available as future Trading Post offerings.
NEW Coldflame Infernal
Description: The strange icy flames cause you to sweat and shiver at the same time.
Source: Trading Post
Model id: