There's not much in the green category. For this tank, you could go with Tramitichromis sp. "intermedius". They're pretty close to green when coloured up. Astotilapia calliptera can also show some nice green hues.
I would maybe suggest one of the Lethrinops such as the "Green face" or a couple of the other ones in which the males are "green." They are a little hard to find though. I would check them out in the profile section.
i have 3 red jewels and they actually calmed my tank down, I have a cool looking Honduran Red Point that gets really dark, almost green. I have them with lake malawi cichlids and they are the ones running the tank, they are bigger though. weird.