In the Xamarin Studio solution pad, the folder containing the Collada file has a .scnassets suffix, and the model has a build action of SceneKitAsset:
Given this, the model is rendered as shown below:
There’s also a Collada build action as well. I’ve never used that option though. If someone wants to elaborate on what that does (perhaps supporting animations embedded in Collada files? just a guess) please add a comment here.