any decent php obfuscator

You could use tools like these:

• https://github.com/pk-fr/yakpro-po (demo) for pure php sources (e.g. not embedded in html)
  
• http://phpprotect.info/
  
• https://github.com/naneau/php-obfuscator
  
• http://pipsomania.com/best_php_obfuscator.do
  

Of course, someone could still deobfuscate it if they really wanted to, but it'dprevent a lot of clients from tweaking/editing stuff.