Enterprise Key Management?

[Jon Molesa]

Does anyone have a recommended best practice and accompanying tool for
enterprise key management?

I'm looking for:
 - Centralized key management
 - Master (Company Owned) signing key
 - Sub-keys issued to employees
 - Best way to handle revocations
 - Integration with LDAP/AD if possible
 - Integration with desktop email clients
 - Integration with desktop gnupg implementations (Windows, Mac, Linux)

I realize this is rather broad, but if anyone has pointers or notes
they would be willing to share, I would really appreciate it.

I came across this http://www.egpg.org/, though it no longer looks
active or maintained.

--
Jon Molesa
jonm at knowclassic.com