The people behind the modeling tool Graphity are working on adding support for Anchor Modeling, and have gotten quite far in their effort. There is a nice photo showing a comparison of the tools on our Facebook Wall, as well as a video showing some of the editing features. Great work!
Graphity is a generic web-based modeling environment, independent of notation, metamodel and rules. Graphity is developed at HAN University of Applied Sciences in Arnhem, The Netherlands; Competence group Data Architectures & Metadata Management.