Matt,
I completely understand the idea of Mobile applications, especially with the explosion of Iphones. My concerns focus around the customer experience. I think it is important to not get wrapped up in technology for technology's sake.
For example I would agree that having a device that could search the inventory in real time , while I am walking the lot with my prospect, has tremendous value. I can become more efficient and become a better resource for my customer, providing value.
However, using my handheld device to enter a customer's information, or review my notes/previous contacts and then send an email would seem to be counter productive, and get in the way of my customer's dealership experience and my person efficiency.
As someone who considers themselves an "early adopter" of technology, I have a passion for the benefits of technology, but I have seen many good tools fail because of their complexity and or difficulty in using them.
Some areas that I see as beneficial include:
quick remote/mobile logging of emails and/or phone to stop the manufacturer time clock for leads
the inventory search function noted earlier
quick and easy trade valuation tool