Well I went ahead and got a D7000 and have it set to modem only mode and PPPoE connected successfully. Iíve tried a couple of remote PPPoE resets and didnít see the issue I have with the ZyXel devices, but I suppose time will tell.
Setup was fairly straight forward, I configured it in modem/router mode initially and then flipped the setting once I had it setup. I had changed the LAN address and disabled DHCP and was happily surprised to see it appear on the network in modem only mode. PPPoE cable in port1 and network cable in port 2 with no configuration necessary. Sync speed is pretty much as the VMG1312-B10A, just a wee bit less.
I enabled telnet access as per michty_meís post (thanks for that
), but am wondering if it is permanent as I had to rerun the command after rebooting. DslStats is working with it, so I am happy although I now will have to think about the purchase of a second one!