We did not have custom cabinets, but ordered Kraftmaid from Lowe's. We didn't want our often used microwave and toaster oven in view when not in use, so we had one of the uppers increased in depth to 18", and had an "appliance gargage" type cabinet made to slide in between upper and countertop increased to 18", also. We have lived in our kitchen for about 8 months now and I love this set-up! I worried about the cabinet doors being open when using these appliances, but our house is a quiet one, with just DH and me, so it has not been a problem at all. Also, for us, having the doors open like this reminds us to shut them when we are done using the appliances, so they aren't perpetually open like they were when we had the old style tambour door.
It looks like you have a great spot to do this where you have planned. Or, maybe you just want the upper done, but I don't have a picture of how that would look.
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Folding glass doors
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