I think you should do a colony of convicts plus some livebearers, preferably just swordtails or platies. I personally recommend the rio mongo or rio claro ones from Ken Davis, he can be reached at
fishfarmusa@comcast.com. Either that or the rio bagaces ones from tuic, which would give you a few more options for tankmates.
Pictures of each:
(bagaces male and female)
View attachment 1520033View attachment 1520034
(mongo male and female, claro looks the same but has a bit more blue and red)
View attachment 1520036View attachment 1520035
Bagaces gives off more of an amphilophus type shape as they mature, if you're looking for a colony of smaller colorful amphilophus. I will warn you however, they are extremely prolific and fast growing, I had a 2.5" female produce 400 fry, and the females can get up to 4.5", so God knows how many a full sized female can make. Regardless, I personally think they're the most unique convict, with the yellow/purple bodies + orange fins on males and yellow/dark blue fins on females, along with the gold spangling on the females in place of the typical orange blotching. Probably the most unique thing about them however, is their purple eyes. It varies by individual, but in place of the typical blue beard of most convicts, some may come with a black chinstrap that gives off a unique profile, especially in breeding dress. I have pictures of all of this if you'd like. They also grow nuchal humps.
Mongo and claro (patuco) however are the perfect convicts in my opinion, not very prolific, only producing 100-200 fry max, and the perfect size, with males only maxing out at 5". As they mature they get (what I believe to be) the perfect cichlid shape, more of a rectangular and blunt shape, sort of like this feral one that was caught in the caribbean:
View attachment 1520037
(this is the best convict I've ever seen shape wise)
But on top of that, they get the red fins like honduran red points, and blue beards in both sexes. Females get that orange spangling instead of blotching, and iridescent teal fins. Oh and they have blue eyes. Again I have pictures of all of this if you'd like. Unfortunately these guys don't get nuchal humps, but their head shape makes up for it.
Really hope you consider, I'd love to see it happen. Big tanks don't always need big fish (though male bagaces can get up to 8-10")