I've Googled and found some interesting projects like PHPTypeSafe as well as a similar class on PHP comments but preferably I'd like to just flip a switch or upgrade to a newer version of PHP that supported type hinting with exceptions???
EDIT | I believe I could catch the error by overriding the error reporting method (which I have already done) and throw the exception there...but again I'd prefer if there was a PHP version which just threw exceptions by default.