As all 30 or so CPEs in our network are Mikrotik running RouterOS, is there any way of running a PPP client and server within each CPE with User-Manager sending backup RADIUS accounting reports to a central database?

ie something like: [ether in > PPP-client > loopback > PPP-server > WLAN out] with User-Manager accounting traffic across the loopback.

My reason for wanting to do this is to get away from having a PPPoE server on an AP running User-Manager which clogs up its hard-drive with thousands of session reports the moment I turn my back on it, all of which have to be deleted by hand 100 at a time.