Depending on the height of the upper cabinets, you may or may not be able to lower the cabinets without affecting the distance between the upper and lower cabinets in a negative way. If you decrease the distance between the cabinets too much it will look strange and be difficult to use all of the counter space.
So given that you can lower then, installation of crown molding above the doors to the ceiling looks great and adds a lot. In my last kitchen we left enough room for the crown molding plus 1” so we were able to install a rope light above the cabinets, it made a nice effect of light across the ceiling above the crown molding and cabinets. Crown molding is not very heavy so the supports for the molding do not need to be huge. We used pieces of 2X4 and cut out a section so it went over the upper edge of the cabinet, this allowed us to mount the molding to the 2X4 and the lower edge of the molding was flush with the upper edge of the door.
Now the reality is that the installation of the molding was complicated especially because of the type of crown we chose, it added about $1500-2,000 to the cost. There were several corners and things that added to the complexity, but it is not inexpensive if you pay someone to do it for you.
Like mentioned before a picture is worth a thousand words, attach one and we can help more.
Ex Realtor, house flipper, remodelor and now building a vintage truck, making friends and fixing my house.
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Building a vintage 39 1.5 Ton Truckhttp://www.1939Cummins.Info