Hi yafusername (yet another free username? *gg*),
thanks for the compliments, and welcome to the Sparrow forum!
Sparrow does not build on the MVC paradigm directly, as UIKit does. However, you should be able to create something similar yourself by creating a controller class (inheriting only from NSObject) that has a "view" property that is an arbitrary display object. Then you could implement the logic of the object in the controller class, keeping the view object "dumb".
One of these custom controller classes could then implement the logic for gesture recognition. (Adding a touch event listener to the view and analyzing the touches.)
It will take some experimentation, but it should be doable!
Concerning the render method of SPQuad: Look into the file "SPRendering.m" -- it contains all the "render:"-methods of the display objects.
I hope that helps!