Hi Marco,
an example to put the JBoss under heavy load is very simple and very complex ;-)
So IMHO 'the general example' you want does not exists.
It depends to the application and the requirements do you have.
We have simple SLSB (stateless session beans) and the server run performant and stable with about 500req/sec and some complex where the garbage collector will reach the limit below 50req/sec.
So you can't give an answer to this question without knowing the requirement.
If you will implement have a performant application you should pay attention to the scalability, JEE support this but not without any costs.