Nanotronics just announced a new feature added to their atomically-precise 3-D microscope. They also announced the Eric Drexler joined their advisory board. I take the latter as a pretty firm endorsement that they are on the critical path to APM. Here is a link to a brief article about it:
Steven C. Vetter
President, Molecular Manufacturing Enterprises, Inc.
4105 Countryview Drive
Eagan, MN 55123