AIRWHALES!!! I think hitch-hikers did that first, but AIRWHALES :-)
Hey, that sounds great though. With all the clockworks in the game, I could see the Clankers working, and the Darwinists could be based off summoners, yet it seems like it's original enough to really need the new class.
I'd think the biggest problem would be creating an easier and more reliable way to make monsters, because monster creation is such a thumb-suck. On one hand you run the risk of having a small pool of options to build reliably from, or you have a large pool of options (like the monster creation rules) that is too clunky.
I certainly want to see what you do with this.