Not sure if you've had a chance to inquire about this, but for my needs, I definitely want the 7.1 multichannel RCA input capability. My guess (unfortunately), is that Denon, and now, Marantz, have completely abandoned the 7.1 inputs on all their new AVR/AVP models (the Marantz Cinema 40 is my last hope of a model that might incorporate them, but I don't think the prognosis looks favorable). If this feature has already become a legacy connection for both of these two major brands, I will start looking for either used units or discounted remaining inventory of last year's models. I would truly like to acquire one of their newer models, but not at the cost of losing the 7.1 multichannel inputs.
PS. If none of Marantz's new models have 7.1 multichannel input capability, Marantz needs to remove that feature from the listed specifications of both the Cinema 50 and Cinema 40 on their website - we already know it is incorrect for the Cinema 50.