I got tired of this. I decided to fix this by using a spring clamp to mount the GPS to a handy dash board vent. This won't work for everyone as you may not have a vent in a good location. This ible is also one of those rare cases where I didn't have to use tools (aside from a knob on the GPS mount). Everything worked out to be the right size and in the right place. So while you may not have a Magellan Roadmate 2000 and a 2005 Ford Taurus, this ible may serve as an inspiration for solving your own GPS mounting conundrum.
Just a note of caution. If you do buy a Magellan product be aware their customer service is abyssmal and their staff are inept.