Elaine,
There aren't too many options besides having students submit a video, which is what the current speech classes are doing. Assuming that the students live close to the school, you could have the final presentation conducted onsite. Another option would be for the institution to hire outside evaluators, similar to test proctors for final exams.
If you come across any other information on this, I would love to hear from you again.
:)
Jane
