What I found out is that this approach executes cgiapp_init() and setup() on *every* request (which isn't desireable as I load my templates there, establish caches etc and these steps should run only once!).

CGI::App definitely needs to get re-initialized for each request. Even if you could find a way to work-around the problems you've found so far you'd end up getting burned again the first time you tried to use a plugin that needed per-request initialization.

So, instead of hacking CGI::App, hack your code. In your setup() you could do something like:

      our $INIT_DONE;
      unless ($INIT_DONE++) {
         # do some cache init, or whatever
         ...
      }
[download]

That way you can do your one-time-only initialization in your setup and it will only happen the first time through.

-sam