I'll just do it like this:
public class IslandProcessor : ModelProcessor
{
public override ModelContent Process(NodeContent input, ContentProcessorContext context)
{
ModelContent mc = base.Process(input, context);
mc.Tag = CreateData(input);
return mc;
}
...
}
And then load it like this:
Island = new Island();
Island.Model = Content.Load<Model>(@"island");
Island.Data = IslandModel.Tag as IslandData;
Works fine and is not a lot of work.