>"I have a theory about B which is that there's a fundamental barrier in being able to completely understand anything of far greater magnitude than ourselves. There are some layers of abstraction of sufficient complexity that it may be literally impossible for all normal people to be able to get their brain around."

Sure, it is more or less impossible to understand certain things. Like the distance and size involved in this picture:
http://en.wikipedia.org/wiki/Hubble_Ultra_Deep_Field

>"The "big" questions (why life, what's the purpose, what's beyond existence, is there anything beyond that, etc) may simply be something we can never understand due to the limited capacity of our minds."

That if you have a need to give everything a greater purpose. Personally I'm quite fine with the idea that I'm just the product of my mom and dad and when I die I'm gone. That is what in my opinion people give religion etc credit were there should be none. They say well science deal with how and religion deals with why. No, religion makes stuff up. And that is the end of that.

Limitations of science and our minds does not prove or justify a belief in a superbeing that goes against everything we know about physics and uhm everything.