Dehydration would not be an issue since John would have a humidification system in there and he would not be "refrigerating" his cigars. Just cooling to 70 or so. John, if you don't mind a personal question... How big is it? Are we talking about one of those little knee high mini’s?, i.e., 20 bottles? Or something hip high? or head high? I think it's a great idea with the following caveats;
1. you'll need to burp it like a coolidoor every few days since it's not wood and doesn't breath.
2. You need to check on the variability of the thermostat and potentially install a different unit. Wine coolers are typically geared a little cooler. I think wine likes it at about 58 degrees.
Other than that, I'd say, line her, pack her, and put her to sleep!