A reputable and knowledgeable keeper of African cichlids reported one of their males to have reached an exceptional length of 10" TL.
I personally have seen some big chipokae, 6-7" females, 7-8" males and that puts them right up there with P. crabro and L. fuellebroni for big as far as big mbuna go. Not counting the uncommon Petrotilapia sp. of course.