Sending email after RIS/AD are done (but before user login)

I am almost finished with my RIS/AD but need to setup one more thing. I
would like for the client to send a given email address mail when both
RIS and Active Directory are done (i.e. ready for user login). I would
prefer not to do this after the first user login because I don't know
when that will be and in our current infrastructure, it defeats the
purpose. My other options are cmdlines.txt (which will only tell me
when RIS is finished not AD) or possibly creating an MSI package that
sends this email out. I am already using BLAT which is a freeware
command-line mailer so scripting should not be a problem.

Is there something in the boot up of a machine after RIS/AD are done,
that I could trigger an email to the sysadmins? Once application
deployment starts in AD, the machine doesn't reboot so using RunOnce
will not work.

RIS and AD work so well together that we don't know when it is done. We
would like to know so we can prepare it for its physical move. Thanks.

.