Hi Hfaun,
You might have already come across this in your research, but the official place to start is the Microsoft CRM 2011 implementation guide http://www.microsoft.com/download/en/details.aspx?id=3621.
This gives detailed information about planning & installing CRM 2011 in both standard and more complex set ups. It will also list unsupported arrangements. I'm pretty sure installing on the AD server is unsupported, but this doesn't mean it won't work
necessarily - it just means Microsoft won't support you if the installation has problems.
If you still run into problems and you are able to, I'd recommend spinning up a virtual server to host the CRM application, so you are not installing on the AD server.
Paul Dowman, CRM Developer