I recently saw another kitchen similar to yours but it had some natural light. I would suggest not painting the top cabinets different from the bottom. Rather than mismatching them, a glaze is a great idea, a pale ivory would soften the look rather than pure white. I also like the idea of a color on the walls instead of just white. With black cabinets, I'd go for a softer, warmer look. If the green is too dark, you might just want to lighten the green. Don't throw out your green. Mix it 50/50 to white or 30/70 or whatever you think, but I think a sage green and black would look great together and the green would bring warmth to the black. The floor and counter top sounds as though they match well enough. Leave well enough alone. See how it looks with a lighter shade of green on the walls, a light ivory glaze on the lines in the cabinets, and - a final touch would be to add knobs that would highlight and complete the whole look. Something moderately decorate, not black and not all green. Either match the faucets and sink, or co-ordinate with them - well, you'll have to go looking. Look online first. You'll find a huge selection. Remember to seal the marble counter top. Keep it nice. Also, you might consider a hanging light in one corner, that gives off a good amount of light - near your work space and/or range. Wish I could see it. It's rather fun. I'm remodeling myself.