URGENT INFORMATION NEEDED

I know I posted earlier today requesting information on scalability and resource issues with PHP4beta2 but I now urgently need to scramble for info to make the case to a client who is bent on going with mod_perl or python(PyApache) as a solution. I only have 24 hours to put this together, I hope someone can help. Basically I need to know facts on the scalablity and requirements on resources of PHP vs. other solutions, can PHP scale well to handle massive tasks, ie. millions upon millions of requests per day and large data transfers. What is the typical resident memory size of a mod_php apache server under load? We were seeing mod_perl httpd's bloat to close to 20mb under certain circumstances, does PHP do this better? Thanks in advance, Paul