I'm running a small local WISP here, about 300 customers and growing, using two RB1100AH for PPPoE servers (for redundancy and load sharing), with authentication by FreeRADIUS server (two Linux boxes for redundancy), not using any database yet - just a plaintext users file where RADIUS attributes are set for each customer (PPPoE username, Cleartext-Password, Framed-IP-Address, Mikrotik-Rate-Limit) and each customer upload/download speed is limited by dynamic queues (disabled for low traffic night hours with some ROS scripting). So far so good... but the wireless network (mostly 5GHz 2x2 MIMO) has its capacity limits, and it would be nice to be able to compete with 3G mobile offers too (low price, high speed... and low monthly traffic limit, low speed after the limit is exceeded). So, I'm looking how to implement (optionally, for people who want low prices and don't need to watch TV over the Internet) such daily/weekly/monthly traffic limits with PPPoE.

Other than RADIUS Manager (commercial proprietary software), and Mikrotik User Manager (not sure if stable enough for production use yet), could someone suggest some easy to implement solutions, ideally based on free (open source) software? Many WISPs will face similar issues soon, so I imagine there will be high demand for such solutions (less so with copper or fiber networks, but even these may have limited uplinks).