I've got an '02 celica. Nothing I've been able to find (that you can actually buy) seems any good. I thought about just getting one of those seat-frame mounted ones they use for laptops and such but it just seems clunky. I've decided to (eventually) just go the custom dash route. Because my center console is so thin (width wise) I'll have to have the iPad in portrait but it's not THAT big of a deal. I contemplated replacing my gauges with it but it seemed like a LOT (and i mean a LOT) of work to make it look nice, plus it would be permanently destroying the dash, vs the center console which can be easily (though not cheaply) replaced.
Also makes it easier for a passenger to use.