Technical resources for Open Access Fiber Networks?

Hi NANOG, Not so long ago I learned about Open Access Fiber Networks. I'm quite curious about how these are actually implemented. I'm able to find boatloads of marketing material and management-targeted boilerplate, but I've not yet been able to find any technical resources. My first thoughts were: * Are these just massive VPLS networks? * Are they just giant L2 networks? I can't imagine that either of the above would scale particularly well. I'm looking for any books / papers / config guides / magic tomes / etc on the subject. Can anyone point me in the right direction? Thanks, Mark