There are as many combinations of stacked molding as there are kitchens. I've used a triple bead pilaster molding horizontally on top of the cabs, then the 6" filler to the ceiling, then library molding on top of the filler with a triple bead accent, and then the crown molding with a single bead insert. Or, for a more simple look, I've used just a plain "cabinet edge" profile piece, then the filler and then a simple coved crown. It all depends on your style, how much other frou frou stuf is in your kitchen, the room you have, and the skill of the installer.

We already had 3" or 4" crown moulding at ceiling. Our KD suggested crown on top of cabs (not Shaker style) and we are very pleased with it. The Shakers were a simple, plain people, but in today's world, the crown softens the look, and will be very nice. Crown moulding on upper cabs depends on how much of a purist you want to be. If one is true to the era, one will also forego the electric light fixtures for candles, modern appliances for wood-burning stove, etc.. ;-) Google "Shaker style kitchen cabinets" and look at the images... gives a custom cab look.

Hi P, Love your bright & clean kitchen! Also, I am a fan of subway tile although on my screen your tile looks very faint, glassy (not matte) and almost disappears entirely, I don't even see any grout! In addition, your chimney hood looks pretty small to scale now that I see the 2nd pic and of course doesn't go to the ceiling or has a flue cover. For me it's the straight line per the cabinets/molding/range hood that's a bit jarring, and then it's not symmetrical with the ceiling beam. But honestly, none of this would be a big enough deal for me personally to sink a lot of $$$ into. Agree that much of this is simply because your kitchen is unfinished. If I were to change anything it would be the straight horizontal line, inspiration pic.

A local lumber yard that mills wood will likely be able to match it for you. We ordered the crown above our cabinets from the cabinet company and the rest that goes around our family room (meets up with the cabinets) was sourced locally that way.