There was a thread some time ago that listed some companies that make mounts for cellphones, GPS devices, etc. I would suggest looking for an alternate mount.
FWIW, I know that in CA you aren't supposed to use a suction cup mount on your windshield but (a) would it really be enforced and (b) if you do it smartly it shouldn't be a safety hazard. To elaborate, I have seen people mounting Magellans and Streetpilots smack dab in the middle of the windshield and thus obstructing the driver's view considerably. Part of the problem is the larger size of those devices. I use a Garmin Nuvi that is quite small and I mount it to the left of the rear view mirror and that keeps it from obstructing my view of traffic and pedestrians.
One of the issues with mounting a GPS device is making sure the antenna can see the sky so being in your windshield is best but perhaps you can purchase an external antenna and you can then mount your GPS below the window lines on your center console, cupholders, or on the face of the dashboard.
http://www.proclipusa.com/home/home.aspx
http://www.arkon.com/