I found this item on Amazon called the Nav-Mat GPS friction Dash pad.

It allows you to attach a GPS to it, and it stays in place with friction.

I think it would fit perfectly above the center radio/dash area

http://www.amazon.com/gp/product/customer-images/B000U5TUWE/ref=cm_ciu_pdp_images_0/105-3303865-1360445?ie=UTF8&index=0#gallery

My Garmin came with something like this and it works very well. Although, I have a semi-permanent mount on two of my vehicles that looks more custom. Thnx, for the photo.

Another option is a vent mount-
1577

The one pictured is for a Garmin but they're probably available on ebay for other brands of GPS.