Note: The selection of directory service properties is disabled because the portal is in an untrusted domain or no directory service import is configured yet.
Security Note: If you are using a high privilege account to import, you will be able to read and import directory attributes that are not normally accessible by users.
This one took me a while to figure out. The fix was rather simple in my case. It was a simple mismatch in Import Connections under the SSP User Profiles and Properties section. One of the connections was named after the NetBIOS name of the domain instead of the FQDN of the domain.
For example, the original connection was named domain when the domain's fully qualified name was users.domain.com. I created a new connection and named it users.domain.com and deleted the connection called domain. This was all done in the SSP's User Profiles and Properties section under Import Connections.
Once I created a new connection named after the domain's FQDN SharePoint decided it would let me map Active Directory fields to user profile fields.
All is well in the world again and I can continue with my late night work.