CI as web service

[eluser]Lima[/eluser]
I have a plan to build web service using CI XML-RPC, PostgreSQL, PHP5, Apache2, and Debian5.
This is my first experience building large web service than can handle a thousand transaction per second.

My question is:
1. Is it possible for CI XML-RPC, PHP5 and Apache2 to handle a thousand transaction per second?
2. What is the best configuration for PHP5, PostgreSQL, Apache2 and Debian5?

Someone who have experience with web service application please give me some ideas.

Thank You

Lima