Are they any plans to add RFC4045?
Or any existing openl2tp effort in that area?
There are no plans at the moment. We've been watching this RFC but have seen no further activity since it was published in 2005. The protocol assumes L2TPv2 too, which isn't a good sign. Adding support will be non-trivial - it will require some kernel work, as well as userspace application changes for the protocol extensions.
What equipment are you wanting to interoperate with? If there is a valid use case, we will consider adding support.