Eran Galperin has posted a few hacks you can use for the Zend Framework's Router system to make passing arrays easy and integrated.

A big advantage to using the front controller in the Zend Framework is the ability to create nicely formatted urls. [...] The implementation of the default router in the Zend Framework (Zend_Controller_Router_Rewrite) does not allow for passing arrays in this manner though, since previously set keys get overwritten if they are declared more than once. This is somewhere between semi-annoying to very annoying, so lets get straight to hacking it into submission.

His patch only changes one line in the Zend_Controller_Router_Route_Module component - changing it from assigning to a conditional checking for the existence of an array and setting it appropriately.