To my opnion, IEEE 802.17 has nothing to loose by extending the application areas of RPRs. With 32 nodes this is only 230.4 Microsecond delay. For 100msec latency budget, with 50msec consumed by the circumfrence of earth, we still got 50ms of switching latency. What is a big deal in saving few micro seconds in RPR rings. Real latency we should consider is the queueing latency in rest of the network for voice applications.
Class based queueing with voice class scheduled first is the solution.