Depends a lot on what you already have in the tank, what you plan to put in the tank also
but if you want just that basic question asked i would say german blue rams would be the best for those sizes
same answer you got on the reptile forums, none with those convicts! you need to sort out what you want with the fish you have already before you get more... you need to decide what you want to do with th convicts that are going to end up either breeding or killing each other, terrorising tank mates and leaving you with a lot more than 2 convicts...
The Convict issue aside, you could consider Apistos (there are many varieties), Bolivian Rams, German Blues. The German Blues are somewhat picky on water conditions compared to the other types of Dwarf Cichlids.
I've got a couple bolivian rams now, and they've been little angels to the other fish, though occasionally bumping heads with each other, though no harm being done.
I would recommend them, but not with any aggressive fish.