Hey guys,
Currently got a Billion 7800NL which while doing all the basic tricks, isn't compatible with either the DD-WRT or Tomato firmware.
Has anyone got any recommendations for a compatible modem, or better yet, can point me to a bargain-priced modem that will work?
You're going to have some challenges in finding a modem or any modem/router that can run DD-WRT.
I would recommend getting yourself a dedicated modem, or use your Billion in bridge mode and then use a stand-alone router running DD-WRT.
I'd recommend a Cisco (Linksys) E3000.
Runs dual frequency wireless in DD-WRT and is also a fairly easy upgrade.
If you don't need the dual frequency and don't need to boost tx/rx power try a D-LINK DIR-615. They're cheap as chips, simple upgrade to DD-WRT and rock-solid.