I had blue acaras & firemouths in a 55g, not perfect but in my case, doable. The really aggro cichlids...Good Luck!
I am going to monitor my fishes behaviour a little more closely and try to see what my LFS will trade or do for me. My GT's are growing fast!
Ideally, I think I would like to get rid of all my gouramis and one of my GT's, and get a BGK with my severum and GT. Then maybe get a really cool scavenger catfish or bichir or something. I have to start researching a bit.