Certification does exist....it's not widely used or accepted because in most cases, companies want developers not engineers.
To add to it, the only thing stopping Software Engineers from becoming members of the above mentioned organizations is a code of ethics (and experience) - not knowledge or know-how.
It's incorrect to say an engineer can "become" a member of one of these organizations, because you're not legally an engineer until you are a certified member.
That's an understatement. Was speaking to a fellow engineer recently, and he claimed that there are really only two licensed software engineers in all of Toronto. We probably have tens of thousands of software developers.
Apart from those two, I've yet to find even a reference for it (let alone a requirement) - which is a cycle because one of the requirements of being a PEO is 12 months of work experience under a PEO (which won't happen as there aren't enough PEOs - the chicken and egg problem).