Theoretical Capacity Planning for ASP.NET Applications

Good afternoon,

I understand the basic theories of capacity planning as it relates to
profiling an existing web site, such as in the examples given in the
MSDN Article, "How To: Perform Capacity Planning for .NET
Applications" [http://msdn2.microsoft.com/en-us/library/
ms979198.aspx]. This assumes the existence of an application to
profile, though.

What is a good way to perform a more abstract, theoretical assessment
of what type of hardware resources will be needed ahead of time?
Assuming that there is a required lead time for hardware acquisition
and the code is not complete or can not be profiled completely to
perform a full profile, what methods can be used?

I have seen some references to using throughput as a capacity planning
tool, but I would be concerned that the issue with that would be that
it is treating all calculations as if it was dealing with static
content - solely basing calculations on bandwidth and not on memory or
processor availability.

Any ideas or references would be greatly appreciated.

Thanks in advance,

Joseph