A. I would understand what applications (or set of applications) are
commonly used by large (>$500M revenue)organizations to
1. Capture project data - estimated cost, benefit and schedule
2. Manage project work flow through a configurable business process
3. Compare estimates with actual cost, benefits and schedule
4. Track project change through time e.g. be able to wind the
clock back to see how estimates and actual changed.
5. Provide flexible, graphical and customizable data analysis
capabilities to the business users for project specific or portfolio
analysis.

I realize many of these requirements are met in part by common
applications e.g. SAP can provide activity based pricing for projects.
 However I am looking to understand how these different sets of data
can be pulled together around managing a portfolio of projects.

B. In addition to providing a list of applications, a summary of their
function and references to additional information I would like get an
understanding of typical ratios of
1. Software costs
2. Implementation time/ cost
3. Ongoing support costs. 

C. What information is there on the buy vs. build decision in this space?

stephen_nz-ga,

MS Project is widely used for many of the functions you outline,
especially managing corporate work flow and tracking corporate project
cost estimates.

Here's a link to the official Microsoft Project page. From this page
you can examine several Case Studies for Project:

http://www.microsoft.com/office/project/prodinfo/default.mspx

The latest version of the product is MS Project 2003.

Hope this helps,

omniscientbeing-ga

Thank you for the link; Project has come a long way since I last
looked at it.  I think it would only partly address my requirements in
that it does not manage the process of idea capture, development and
evaluation instead has a strong focus on detailed/intra vs. portfolio
project management.

You comment has made me realize that I am not able to define this
question well enough for this forum so am cancelling the question
until I can.