Freakgecko91 - I believe if the tank is large enough for instance a 90gal then peacocks and mbuna are able to co exist but if the were to be put into a small tank say 50gal then the peacocks being the less aggresive species would be attacked and stressed out.
For the stock i would reccommend Julidochromis species. These are Lake Tangaynikan species that stay relatively small around 3 - 6 inches. And you could quite a lot to the tank Species such as
Dickfeldi
Transcriptus
Regani
Merileri
Other species that can co exist in the same tank with these guys are
Altolamprologus species
Daffodil Princess Cichlid
N.Brichardi
Tropheus
Hope this gives you something to think about