Flashing EoL ISP devices

I've swapped out most of my known gear - stuff I've flashed *WRT's to - to sites (mostly friends & family) so that they have good, trustable gateways.

I've ended up with a whole bunch of ISP-provided hardware that actually seem quite nice, but there doesn't seem to be a custom ROM/firmware stack/community out there.
Some of these devices include:

  • DrayTek Vigor2860n Anx.A
  • NetComm NF18ACV
  • Hauwei B315s-607 (with built-in modem)

These devices seem quite nice - at least in terms of hardware capability - but the software stack sucks, mostly due to being crippled or locked down by the ISP, meaning I probably can't trust these end-points.
Some common features that sets them apart from some of my preferred/flashed gear includes:

  • GBE interfaces (rather than the 100 meg I usually get on my cheaper off-the-local-shelf TP gear)
  • xDSL interface - that the local market has moved beyond, so that's a useless appendage
  • FXS ports for POTS/fax

Since ISP seem to consider these devices as loss-leaders and customers get a new one every time they change ISP, I can get more of these devices than a can shake a stick at, probably in bulk by weight!

What is the current state of development for such devices?
They don't seem to be supported in OpenWRT, Tomato, Gargoyle or any of the custom firmware stacks that I frequently use.
I mean, they're so incredibly easy to come by, I really do not mind the risk of bricking a few in the pursuit of learning to get one over these black boxes.

Is there an existing community out there for these kind of devices?
Where could I start?

An help would be greatly appreciated, thanks.

The Draytek should be supportable (but will require significant porting efforts), the others probably not (NetComm, no - Huawei, not enough information, but unlikely).