I agree. We get burned by the Damaso Effect: the good MBAs work on billion-dollar private equity deals and the ones who fail out end up going West and managing nerds. Further reading: http://michaelochurch.wordpress.com/2014/01/05/vc-istan-8-th...
So the initial invite would be for E6s+ at a few organizations (Google, Facebook, others?). Those people would know others they can vouch for, at either the "senior" level (the E6+ level) or at a "junior" level, but who are on a trajectory to make the "senior" level, eventually. At some point, this group would need to establish either which schools, or which certifications (i.e. MOOC programs) qualify someone for "aspiring junior" or similar roles, much like the bar. Or it could be entirely "project based", i.e. you show the organization some work you've accomplished, and the source code, in order to qualify. I haven't fully thought this through, so I don't really know how to get this right.
Given enough cachet, this should allow SDEs to form partnerships, with relatively little "reputation verification" required from their clients, much like how for most lawyers and doctors, people don't really care which one they go to (at least at first), just that they're seeing someone qualified.