Sounds like you want to put your scripts into a deamon and map the calls to aliases or C-wrappers which do the communication with this service.

But I'd rather go first for SuicideJunkie's suggestion to start perl from a ram disk.

Far less trouble and brain needed... otherwise too many side-effects to be considered...

UPDATE

like

• forking for simultaneous access
• setting uid of the user
• restart on fail
• adjusting special vars and ENV
• avoiding possible exploits

The only overhead you could save is for the compilation (like in mod_perl or FastCGI), but does it worth the trouble?