Well there are already several such systems. University provides accreditation or certification via a CISCO or Microsoft style exam.
Your approach has a fundamental problem. Who pays for it? If I pay to take your test and get a poor score then I will simply never tell anyone I took it. If I do great I will boast about it on my CV. In that case I might as well go with a Microsoft/CISCO style certification because it is well known. If the employeer pays for it then I will still need to take five of them as each employeer will want you to take a test.