Brett, thanks for the response. I agree, I can't find a documented method and can't see how I could achieve this with config files or the DB.
The reason I wanted to is connected with Report Builder and when it's used against SSAS based models, the default (initial) save directory for the users is annoyingly wherever the models are stored. I have a work-around by moving the models to the Home Dir and hiding them in the list view. You asked!
Cheers
A