Are there any Active Directory configurations supported, where forest contains no Global Catalog?
EDIT: Since it was a prevalent comment to the question, I will answer it here: I am working on a product and QA requested that it must work in environment with no GC is present at all. Hence the question: are there conceivably any environments which don't have one.
Active Directory Directory Services: No. You need at least one GC
Active Directory Application Mode: Yes (to my knowledge, you don't need a GC)
As Massimo asks; Why would you want such a thing?
You need at least on GC, your first domain controller is setup by default as a Global Catalog server.
As many have said, I can't understand why you want to do this. If you have multiple domains in your forest, you really need a GC per domain for them to communicate effectively and if you only have 1 domain in your forest, then your GC really doesn't add much overhead.
This is a bizarre request. According to the TechNet article on GCs, in a single-Domain environment the only absolute requirement for a GC seems (and I do say "seems") to be for GAL lookups in Exchange, but all the same I'm failing to understand why creating a GC could be something you would want to avoid.
The GC is the system against which you actually authenticate. If you have no GCs you can't authenticate. Hit TechNet and you will see this pervasively throughout the documentation.
In a single domain environment without Exchange you don't need a GC, even with multiple sites. GC has got nothing to do with locating domain controllers in this scenario.