Ok, I have done a bit more work on these, using the Site that Jason recommended, this is what i have come up with... not sure which icon I want to go with, the pillars or the mic. But the different levels will have a different colour laurel.

• Voice Recorder - Red
• Audio Editor - Green (proof2)
• Webcaster - Yellow (Gold)(proof1)
• Instructor - Orange

Let me know what you think!