There are PHP Compilers available, there's even a PHP->.NET compiler. but this will only run on Windows (possibly Mono), of course.
PHP Compilers tend to cost $$$, and since PHP (out-of-the-box) is interpreted, so you cannot compile it, only obfuscate it.
But most PHP product developers will argue the money is in supporting your product, not the product itself (that's why Community Server's source is available)