This is very good advice. I have moved many of my plugins and apps from using models to modules because of the performance gain. There is nothing wrong with the models implementation, but it's really meant to define tables and that's it. Functionality that doesn't belong in a controller should go to modules.
Some other advice that I have been gathering for my own deployments is to use Nginx instead of Apache. You will see an incredible increase in the number of requests per second that Nginx can handle over Apache. Also setting up an Nginx front-facing server that is proxying requests to another server running Nginx + web2py might be a good idea for lots of traffic. Have the front-facing server handle the SSL traffic, and maybe even enable caching on the front-end as well. When you need to add another server to handle increased traffic, this front-facing Nginx server can be configured to load balance so that you can scale as much as you need.
