CA and Client Certificate management associated with a product.
For added security, hosting control panels, client oriented web pages (and WHMCS admin pages) can be protected from attacks from outsiders when access is limited by Client Certificate Authentication. At the moment I do the process of issuing and revoking client certificates signed by your own Certificate Authority signature with a separate tool, but this could be nicely integrated in WHMCS, where all relevant client information is available. Certificate files could then be send to the client for manual installation. In browsers of the Mozilla family installation can even be automated of which an example PHP script is available : http://sourceforge.net/projects/php-ca/
Would be nice when certificate issuing can be associated with a product. At the end of a contract, for instance when hosting plan expires, the certificate should be revoked and an updated Certicifate Revocation file should be generated.