I suppose you have looked into ProclipUSA? I have those for the iPhone, iPad and the Blackberry. After trying a lot, they're the best ones I could find, I specially like that you don't need to attach cables to the device itself, they can be like a docking station with a cable passthrough. You just slike the tablet/phone, and it's charging/tethering.
That's a very odd shaped dash. If the Proclip does not have a satisfying solution for you, I would try to use the cig lighter socket somehow, perhaps even ditiching it and the plastic mount around it. Direct connect whatever is connected there already and figure out a way to adapt an aftermarket holder in there, IF it's at all visible to the driver.
Did you glue a clock/chrono to the upper left part on the gauge area? You could take that out (it looks out of place there) and fit a round base for an iPhone holder. If its stock, well, forgive me. :-)