Since we are talking about using a dedicated machine for each server, you might consider adding a third machine to do the proxy work; this will make your setup even more flexible, as it will enable you to proxypass all requests not just to one mod_perl-running box, but to many of them. This will enable you to do load balancing if and when you need it.
Generally, the proxy machine can be very light when it serves just a little traffic and mainly proxypasses to the mod_perl processes. Of course, you can use this machine to serve the static content; the hardware requirement will then depend on the number of objects you have to serve and the rate at which they are requested.
Figure 12-10 illustrates the three machine model.