Another update, I've added the ability to pass in string skeleton/animation data to the skeleton controller. This allows you to build the animations at run-time. Useful in cases where you want to download the animation data or read it from disk (Not bundled in a Unity Text Asset).
Jmcguirk, thanks for the feedback! I've added the ability to play multiple animations to the skeleton controller similar to what you did.
I'll be adding the Animation State changes and shoring up the implementation to look more like Libgdx. On the performance topic, I'm seeing 5 draw calls while running a single spineboy animation even with sufficient Z-Spacing. Once I add in a second/third animation like the dragon or goblin it spikes up to 15-20.
I'll have to look and see what Orthello is doing under the hood, but that performance is not scaleable. When testing on a mobile device it didn't look like the number of game objects was the current bottleneck. I really see the performance degradation when the draw calls spike up.