Yes, there is a walk-animation changer at
http://shaklin.net/. Click on the link and you should see a bunch of zip-files; search for the one named "shaklin_model_animation_changer.zip".
Just so you know it is actually a hacked object which will appear in the decorative section, under "miscellaneous objects"; it costs 6 simoleons and resembles one of the Maxis pink flamingo ornaments.