The general idea is

dev.pl

use lib '/my/svn/work/dir';
use MySweetApp;
MySweetApp->run();
[download]

prod.pl

use lib '/production/dir';
use MySweetApp;
MySweetApp->run();
[download]

cust.pl

use lib '/production/dir';
use MySweetApp;
MySweetApp->new('notdefault.config')->run();
[download]