Right now your system uses autoloading in itself, but ZF code is still filled with static require_once calls, some of which cascade to other require_once calls in other files (check Zend/Session.php for example).
E.2.2 talks about how to optimize zend framework by getting it to use full autoloading with stripping out unneeded require_once calls.
There is also a larger discussion about autoloading performance increases in ZF at framework.zend.com/wiki/display/ZFDEV/Performance+-+Requiring+the+Autoloader
PS!!! why am I not allowed to post above links as links but get some message about “administrator not allowing to link to those sites” ???