The size of uppers that you can use depends on how much crown molding that you want, as well as you understanding that tall doors have the tendency to warp over time. Which is why tall ceilings tend to have stacked cabinets over having taller single doors. You can do: 42" tall cabinets, with standard or stacked crown, leaving space on top. Standard 42" cabinets with 12" of molding, which can be top heavy. The corner cabinet shown below is 42", with about 6" of molding, and the lower wall cabinets are 36" with the same 6" of molding. [[(https://www.houzz.com/photos/kemper-echo-wine-bar-traditional-wine-cellar-phvw-vp~8377733) [Traditional Wine Cellar[(https://www.houzz.com/photos/traditional-wine-cellar-ideas-phbr1-bp~t_755~s_2107) by Other Metro Kitchen & Bath Designers ProSource Memphis 54" tall single door uppers, with no molding, which can really highlight the unlevelness of the ceiling. 51" H cabinets with 3" of crown, which has the same out of level ceiling issue. 48" single door cabinets with 6" of stacked crown molding that disguises the out of level of the ceiling. Same with 45" H cabinets and 9" of a stacked crown molding. Lots of molding can be just as expensive as the taller cabinets. And tall single door cabinets can warp much more than their shorter cousins over time. The corner cabinets shown below are the 48"H with the stacked molding to the "ceiling". [[(https://www.houzz.com/photos/dynasty-omega-showroom-vignette-transitional-kitchen-phvw-vp~8549929) [Transitional Kitchen[(https://www.houzz.com/photos/transitional-kitchen-ideas-phbr1-bp~t_709~s_2112) by Other Metro Kitchen & Bath Designers ProSource Memphis 30" cabinets with 18" cabinets stacked on top, and 6" of crown molding, which can be a more expensive approach because of the stacking. (Same with 33" cabinets with 15" stacked on top, which would be more proportionate to the 2/3-1/3 pleasing proportions.) The pantries below show the 84" H cabinets (same top alignment height as 30"H cabinets) with separate 18" H cabinets stacked on top. The seam between the two on the side is concealed with scribe molding. [[(https://www.houzz.com/photos/mudroom-organization-by-kemper-echo-transitional-laundry-room-phvw-vp~11312364) [Transitional Laundry Room[(https://www.houzz.com/photos/transitional-laundry-room-ideas-phbr1-bp~t_753~s_2112) by Other Metro Kitchen & Bath Designers ProSource Memphis "Prestacked" cabinets. that are 45" H (which in my medium priced line that I use, simulate 30" with 18" on top) This is my Kemper display with the "prestacked" uppers. Note that the oven cabinet had to have a refrigerator cabinet stacked on top in order to line up. [[(https://www.houzz.com/photos/kemper-showroom-vignette-contemporary-kitchen-phvw-vp~8376626) [Contemporary Kitchen[(https://www.houzz.com/photos/contemporary-kitchen-ideas-phbr1-bp~t_709~s_2103) by Other Metro Kitchen & Bath Designers ProSource Memphis

In my old apartment we had 9 foot ceilings and single uppers that went all the way up--the top of the doors was maybe within 4 inches of the ceiling. The cabinets must have been nearly 5 feet tall. Yes, we used a step-stool to get at the stuff on the top shelves. We kept infrequently used things up there--the electric frying pan, some nice serving dishes that tended to only come out at holidays, things like that. I remember once reading guidelines about what the maximum cabinet height should be and ours were well beyond that. But we never had any issues, even though they were ancient (not sure if they were original to the 100-year-old house, but if they were installed after the 30's I would be very surprised), and had inset doors. Modern hinges should only improve the performance.

Can't, sorry, I live on the other side of the country now. I did have 9' ceilings. If you are worried about how it will look IRL, do a mockup. Get a large roll of butcher paper (the brown stuff), and tape it to a wall. You can do it outside if you can't find a workshop or some other high space. Then draw the doors, a window, base, and crown. Better still is to have a carpenter do a mockup, with the real millwork, on a sample wall. The wall does not have to be more than a few feet wide. I would only do this in an expensive house, obviously. In fact, if you are getting this fancy, you probably should have a designer, and that person can supervise the mockup. IMO this is the only way for a layman to get a good idea of how the elements will relate in reality. My design was a "modernized" version of a colonial house, almost Shaker, with flat stock mouldings and a flat crown. That's probably not what you are thinking about, so it would not help you. Good luck.

Probably the biggest I'd go just based on the trim around the door I see there. Unless you are going to re-do all your trim and baseboard as well, I've always felt that crown needs to be within a certain size range in relationship to your other trim. When I see some of these modern McMansions that have like 6-7" massive built-up crown next to 3" casing it is kind of ridiculous.