Not to rain on your parade - it's a great idea, but I think its time has passed. With inexpensive tablets out there that can handle input and output to HDD and/or flash storage, and do everything else in a photographers life like email, contacts, maps, browser, GPS, read books & mags, surf forums, etc., etc., etc., this just doesn't make sense. It seems like just another gadget to carry and keep charged.
I guess your job is to convince us of what it will do that tablets and other already established storage units can't do. The cheaper devices are the same price as tablets. Heck, for price of many digital storage devices, I could forego the tablet and get a proper laptop. Some are even more expensive than a MacBook Air!
It all comes down to filling a niche that is currently empty and I, for one, don't see it.