Deployment scenario

Hallo,
I know I asked similiar questions before, so please be patient.

When I want to make sure 1500 consecutive Hits are possible for a WO App, 
what do I need in Hardware terms?

Xserve 2GB Double Processor with maximum memory...- How many approximately?
A server for the DB in Addition?

How many instances? 1500? Probably not...

Can Apache be a bottleneck? I need to run more than one WebServer probably?

A similiar App was programmed with aspx and runs on two Application servers 
with a load balancer in between and with a third server for the database. 
Will that be enough for WO to meet the criterion of 1500 consecutive hits?

Thanks for some input.

Regards

Ute

Yes, I know it depends on the App, but ...