>Is there a performance hit going through each subclassed layer or is it negligible?

I'd rather classify it as negligible. I've worked with a Codebase type framework, where each class you make has at least a grandparent, or in most cases a grand-grand-grandparent, and it's been pretty fast, even on the 400 MHz box I had at the time. Didn't notice any significant slowdown, but then didn't really measure them up.