I created a multimedia assessment for my own online students. It does not log scores, but gives a very good indication of the students level and tests most areas, except listening.
It might be what you are looking for, so I include a direct link: http://www.linguaspectrum.com/leveltest ... /index.htm
This is a very extensive test and can take a long time to complete. If you have an idea of your student's level, you can start them at that part of the test. When the student can no longer answer most of the questions correctly, you will have a reasonable assessment of their ability.
I hope this helps.