What we'd like to do is use amateur radio for some university research
projects. Specifically, we would like to use AR equipment in sensor
network research. Sensor networks are basically like APRS without people
at the transmit nodes, and more than just position information is
reported (maybe temperature, etc). Also, multi-hop relay may be employed.

I would say find a comercial frequency and use it. YOu did not mention the
frequency that you would be using . If under 30 mhz it will be would wide.
If in the UHF and above you may go ok. Just remember you will be subject
to a shared frequency and others may use that frequency.

Sounds like one way or beacon modes to me.