I just submitted a patch to php.internals which includes CRL generation support into PHP's ext/openssl. You can also get it here:
ext-openssl-crl.patch. Hopefully It will be integrated - I'm working on a CA solution based on PHP and
phpSATk which will be used for certificate management in a WPA-EAP/EAP-TLS environment. So hopefully it will be integrated fast (- well I do not have big illusions here
)
UPDATE: There was a problem in the extension source - updated