N-Tier Web Applications, Application Servers and Python

[Orr, Steve]

I'm looking to architect a 4-tier or N-tier Python web/CGI app with
database connection pooling for high performance. Is there a Python
equivalent to Sun's now famous Java PetStore application? (Or something
like this link: http://www.developer.com/tech/article.php/606971?) Any
Python recommended links/white papers? I've glanced at various Python
utilities and frameworks (including Twisted) but what I really need is a
fairly complete and robust sample/demo app like Java PetStore. If there
is no such Python equivalent then there OUGHT to be.  ;-)

TIA,
D. B.