This sounds like a cool system. However, it also sounds really expensive and requires participant set up on home computers. How many problems did you pick out in that last sentence?
I really don’t think that this is doable for widespread adoption, but it could work for some situations. Purely distance programs could probably make this work. The package could just be a requirement of the program. If it were utilized by most of the courses, it could be a valuable asset.
This could be good for testing centers. ETS could require these to be set up in local testing centers, particularly in those areas in which they have had problems in the past. Essentially, trying to keep the centers honest as well as the test-takers.