you could always go for the smaller cichlids to fit more in, so you get more of a mbuna aspect, fish such as firemouths salvini's etc. and those are usually the first american cichlids people get into, they tend to be forgiving about overstocking and water parametres, however if youre looking for a big personable pair there are some Vieja species that grow a little smaller than Synspilum, just have to be careful that you pick the less aggressive species.
I'm sure if you brought them small then they would be fine in the tank as they grow up and get used to each other.
would you be buying a group to get a pair? or just hope you get male and female?