I have the Marvel 6BARM fridge that I use exactly as you describe. The fridge is considered dual zone, but it only has one thermostat setting. The way they achieve dual zoning is with an adjustable glass shelf. The space above the glass shelf is close to the thermostat's setting and the space below the shelf is 3-5 degrees warmer. I set it at 45 degrees and use the top half for whites and beers and the bottom half for reds. The beers aren't ice cold, but they're cold enough. It is loud. But, I found a way around the noise. I lined the space with some Owens Corning purple styrofoam insulation that I picked up at Home Depot. After treatment, the noise level is now down to a "Normal" room level according to my sound meter iPhone app. It's about the same as my main fridge now. I bought the fridge for about $900, so I got a good deal. It's a decent fridge, but I would never pay $1400 for it. You should also look into Perlick. Do a search on GW and there should be a link to their online outlet for some good deals.

Positano, when ours was new, I could here the relay click (it was honestly more like a twang) when it cycled on, but it was quite quiet while on. The service guy guy came and checked it out because I was concerned the twang was some fan parcially stuck. He explained that it was the type of relay they used, and that after a while it would be quieter. He was right; know we don't ever notice the relay, except if I have my nose in the fridge looking for something when it kicks on.

I just bought a factory seconds from Perlick but it is the "C-Series" and it is louder than their Signature Series, just keep that in mind. For my wife and I who are upgrading from a free standing unit that is almost 15 years old from Sam's Club, the sound is just about the same as that old unit.

My only experience is with smaller countertop wine coolers, but one I used did manage to keep about a 10°F difference between the topmost and bottommost shelves. Not divided into neat zones though; the middle shelves are simply between the two temperatures, the lower the colder. I've never found the standard temperature rules for red/pink/white wine to necessarily be the best though, with for example, shiraz tasting better when served cooler than cabernet even though they're both red, so the variable temperatures proved useful. Some wine coolers work like most refrigerators - they use a compressor. Others don't use a compressor, which have the side benefits of being silent and making more efficient use of space. Both varieties can be made to cool different compartments to different temperatures if designed carefully. You may want to crosspost this question on the GW wine forum too.