Aside from DogSteps, this new book appears to be one of the best resources for the study of canine structure and movement out there right now. It has video clips of gaits, xrays, 3D displays of the muscles involved in various movement, etc. all recorded from 300 dogs from 32 different breeds...

http://www.biomedcentral.com/1471-2148/11/73/abstract Vanishing native American dog lineages Santiago Castroviejo-Fisher email, Pontus Skoglund email, Raul Valadez email, Carles Vila email and Jennifer A Leonard email BMC Evolutionary Biology 2011, 11:73doi:10.1186/1471-2148-11-73 Published...