I recall reading, once upon a time, that if your app required specific hardware you had to deliver to Apple, at your cost, said hardware. And something about it never being returned. I went hunting through my contracts but couldn't confirm.
If it's brand-new hardware and you want a "Made for iPhone" logo on it, I'm thinking you have to sign up for MFi, at which point you'd probably find an answer to your question.
OTOH - you're using TCP/IP? Does the user specify an IP address, or is it Bonjour discovered or something? I'm thinking that maybe if you simply setup a camera in your DMZ and gave them the pinter for control that they wouldn't need much more than that. Don't give them a brick wall to stare at, but don't give them your op center either

Maybe a camera in your hallway - but hang a big sign telling people Apple is watching!