The PDP-11/70 core is now available at OpenCores, see

http://opencores.org/project,w11 archived on
2010-07-25

The documentation is admittedly still rudimentary. The backend handler is still in Perl. This and many other things are on the TODO list for the future.

2016-12-03: the link shown above shows the status of the OpenCores page in July 2010, shortly after the repository was created.
For original note see posting to cctech@classiccmp.org archived on
2014-10-03