You could always change the file extensions to .html instead and then use this in your htaccess:
AddType application/x-httpd-php .html
That will make apache use php for .html extensions. You could also use any other extension such as .ico, .ttt, .any just to completely confuse any potential attacker but note that they may still get the server specs from a head request and if it only reveals php and no perl then it may still give the game away.
My helpful sig is on vacation trying to loose some weight. It got a bit fat and caused a few problems but it will be back at some point!