In my 112g I have my 2 oscars (8" and 5") and a male convict (4")...I used to have a blood parrot (4.5") and a gold sev (5.5") which are now in my 90g with my female convict (almost 3") and a juvi JD (3")..[Ah sorry for all the sizes

] In a 120g, You could easily pair an oscar with any of these fish, if not maybe 2...
-Severums are beautiful, my gold male is soo peaceful, but a little shy (unless he's with my bp [his best friend that he grew up with]) so i can see why some people have problems with them being with oscars.
-I have heard JD's can match an oscars temperment, and they are really colorful when they are full grown.
-Convicts are pretty fast growers (I added mine to the tank when he was maybe 2" and he definately held his own against the 2 o's.
-With blood parrots, I believe their attitudes is influenced by what fish they're raised with, and how much RD is in their blood. At my dentists office, they have a large tank (not sure what size) with 2 bps, and angels, and rainbows. Mine had been raised with the severum, but also a blue acara and a texas in a 55g (got the bp and sev off of someoen), so he is a little more aggressive, i'm sure he really had to stand up for himself in that size of a tank with those fish.
Why not go with 2 oscars? I have an albino tiger, and a tiger so that it at least adds a bit of color...
HTH...