Hi Pentaxdude,
I've been away so very late to the game in this thread.
My thought is this: screw those customers!
Not the easiest to accept in a down economy, but if you have potential clients who are making their decisions based on what type of camera you have, I would be very wary of what type of client they'd be (ie. clueless and nit picky about everything because they don't know any better).
It's not easy to turn down a client and potential $$, but I know for my little business (video transfers), I stopped catering to that type of client.
Have I lost business?
Definitely.
Do I have less stress and end up working with clients who understand and appreciate my work?
Most definitely.
I would, in all seriousness, print a Pentax label and put it over top of the Ricoh spot.
Use it as in ice breaker - potential clients will no doubt ask with the label represents. That's an opportunity to be humorous over it and say that some clients scoff at the fact you don't use Canon or Nikon which is silly because it's the photographer, not the camera.
No kidding, I think it'd be great. Plus it would also show your confidence in who you are as well as in the equipment.
Best of luck,
Keebler