check out the Xway from Tetrax. I've had one of these mounted in my car for several years and several phones. You just add the small magnet to the back of the phone and it holds it all perfectly. Super strong magnets hold it in place. I've been rear ended and the phone didn't drop. It's awesome.
Tetrax 72016 XWAY Smartphone/iPhone/GPS Magnetic Holder, Airvent Mount : Amazon.com : Cell Phones & Accessories
if you do a web search, you might be able to find an old link for a way to mount the xway to another universal phone stand so you can mount it vertically to the top of your dashboard.