This is the most common profile for crown. It will be available, just get the right height. I suggest a millwork lumber yard rather than a box store if you want to get primed real wood for a decent price.

Yes, we're having the cabinets made. They're framed cabinets from Kraftmaid, and come in 3 inch increments for height. I could have gone with 30, but then there's a lot of room left at the top, and I don't want a big crown. 33 inch gives me more storage space and still leaves just enough room for a 3/4 inch or 1 inch crown at the top. I want something straight as Sophie Wheeler suggested, not something that is angled. They have something called "solid stock" that is finished on 3 sides and gives you some flexibility in placement. Same for the light rail - just a straight edge mounted so it comes out slightly beyond the bottom of the cabinet.

Related to this, what is the thinnest trim/molding a top of kitchen cabinets you can get away with? We have 8FT ceilings and 42 inch cabinets and my contractor wants no trim but my designer HATES the idea and feels we need to finish it off. The cabinets are white shaker style and our home is not modern, but contemporary leaning toward the traditional side. Its an old house being renovated so has elements of both the 1940s and 2000s. ANY suggestions would be awesome! Of course this issue is coming up at the 11th hour for some reason!

You've got several problems. If you buy more of the same crown from your cabinet company, you'll still have to deal with the gap above the corner cabinet. If you raise the existing crown to the ceiling, it's very unlikely you'd find unpainted crown that matches it's size and profile, plus you'd then have to deal with a gap between the cabinets and the bottom of the crown. Here's what I would do. Choose the new crown mold you want for the rest of the room and measure it's height (how far down from the ceiling it comes). Make a mark on the wall at that height, then use a level to transfer that height to the stained crown and mark it. Then, trace the old, existing crown's profile onto the wall with a pencil. Now you have a mark where the bottom of the new crown will intersect the old crown, and another mark where the old crown will have to be narrowed to fit underneath the new. Carefully remove the stained crown from the corner cabinet. Next, build a frame above the corner cabinet that's the same height as the new crown, and that extends beyond the cabinet to the point at which the new crown will intersect the old. Now, install the new, painted crown around the kitchen and across the new soffit. Last, run the old crown through a table saw and cut it down so that it fits underneath the new crown. With me? This is a tough one to visualize.