I also have maple stained espresso cabinets, mine looks just like the animala's island, but I had the same issue- my cabinet maker could not stain maple dark. He tried to get the color I wanted, it was not working, so I ordered cabinets from a line he carried, Crestwood, so I could get that color I wanted, and he built all of my drawers and roll-out trays for me.

Yes, it seems that the factory can do it, but it's difficult for a cabinetmaker.

The problem with maple is it is not porous enough to soak up the stain. Stain usually just lays on top in blotches. There are two kinds of stain. A Pigment stain will not evenly color maple. Maple is too dense to soak up the pigment. Dye stain will color maple though. It is harder to apply and more can go wrong though. Fine furniture makers use it and I am sure many factories do as well, but it's probable that your cabinet guy does not know how to use it properly. You could also use gel stain, but that's almost more of a paint since the pigment just sits on top. Some people also mix the stain in with the poly finish, but if the finish gets a stratch the maple color shines through since the wood is not actually stained.

Was your cabinet guy aware in the beginning that you wanted the cabinets dark? If so, it seems to me that even if he does not know how to use dye stains, he should pay someone to do it who does know how to use it. He should have told you up front that he could not stain the maple dark and could have suggested a different wood for your kitchen.

Here is a link that might be useful: Stains

You might want to try posting this over on the woodworking forum and the decorating forum. There are folks there that are great at this - and can probably recommend something. I'm thinking a wood conditioner, but I'm no expert.

Could someone else do the finishing?

Perhaps they can be skinned, sort of like refacing, or like Ikea cabinets where the boxes are plain and you just stick a chunk of wood on the exposed ends. Of course, you need full overlay doors for the best effect, but it is also possible to skin the fronts if required.

The cabinetmaker could order pre-made & prefinished doors/ drawer fronts from a company like Walzcraft.

Or, you can opt for a different wood like walnut. I would not stain or paint the cabinet interiors but leave them the light colored wood.

Here is a link that might be useful: Walzcraft