I thought I was pretty clear about this one: "As about all the other
possibilities (running two apache instances on two different ports/ips
or running one php version as cgi) -- they are really not an option for
me."
As even Adam in his book mentions, his solution is a solution for testing
Adam Trachtenberg's "Upgrading to PHP 5" (O'Reilly 2004) describes how to do
this (more or less) in 'Appendix C: Installing PHP 5 alongside PHP 4.'
Basically, you want to install and configure one version of PHP as an Apache
module (--with-apxs) and the other in its default CGI configuration.
