You might (or might not, I don't know) be interested to know that I am using this version of the OpenWRT firmware to integrate these devices into Solarwinds Network Performance Monitor. I work for a mid-sized company who support a handful (31) of external workers on DSL lines. They don't make us enough money to put enterprise grade kit in place, so I'm trying to make the best of a bad situation and use the ISP provided equipment. However it's preferable for our helpdesk to have access to stats when troubleshooting problems, which is where Solarwinds NPM comes in. The rest of the 4000+ nodes on our network are in there, so these DSL lines should be too.
At the moment I'm using SSH scripts to log in to the ECI modem remotely and scrape stats (via /etc/init.d/dsl_control lucistat as it's very machine readable) and then powershell at the server side to populate some information about the interfaces (NPM can retrieve the interface usage data via SNMP but not negotiated speeds, so I scrape them from the dsl_control output then powershell them into the database via the Solarwinds API).
Ideally as the devices are remote I'd like to use SNMPv3 to query them. I know that the version of snmpd you provide available via opkg claims to support SHA and DES (not ideal but better than plaintext SNMPv2) but I'm having a bit of difficulty getting it to work. I wonder if perhaps snmpd is lying and isn't compiled against openssl at all, so has no encryption capabilities.
Also your dsl_control script has inconsistent outputs - when referring to values that have an up and down value you suffix each var with _up or _down except signal attenuation, which has a _up but no _down
Either way I'm very grateful for your OpenWRT images as my attempts to build my own, either via the full toolstack tree or the image builder would never boot the device!