Host bypass custom build CGI

Can I bypass a web host's mod_php with a
separate, private PHP running as CGI?

Background, host won't upgrade its mod_php.
I may need 5.2.9 bugfixes, depending.
They won't mind if I do it, but won't help.
They're nonprofit.

The question is whether it's possible.
I have shell access, but not root; assume
no sysadmin help or opposition.  I have
gcc from shell. OS is RHEL of some flavor.
Their Apache offers mod_cgi.

I'd rig a copy of PHP 5.2.9 to run as
pure CGI.  I'm fine with the slowdown.
I may be adventuresome and try 5.3.0 RC.

This host expressed terror at a minor
upgrade, PHP 5.2.6 to 5.2.9, which
it termed a "MAJOR system change"
- their SHOUTCAPS, not mine.

User disruption was the worry claimed.  Yet
they routinely do mass notices/reboots for
kernel upgrades, MX change, etc.  Go figure.

So I reckon best to use a custom PHP
behind their Apache 2.  Then I can leave
them alone.

There are other motivations, like PECL
modules which they wouldn't install for
lack of manpower, they said.