Jau are definitely an option, but they are like bullies of the SA catfish. They have a nasty temperment. If you don't feed them constantly they will look at any other fish as prey and start taking bits out of fins, tails, or just bit the fish in half if it can't swallow it. This is from personal expirience. Another consideration is even though it gets much much larger than rtc and tsn they grow much much slower. Eventually you would have to keep it in a seperate tank until it could catch back up. They grow fast to about 16", then it's only like 1/2" per month from my expirience. I will have to house mine seperate after my rtc, tsn, rtcxmarble hybrid, and channel get's larger. Irridescent sharks of a large size would work great and give you some upper level activity in the tank, paroon sharks also come to mind, but as with the jau, they get massive. A member on here had some sucess keeping a yarelli in a large warm water tank even though they are supposed to be cold water fish, and they can get to 5', but have teeth so it's a risk. Marble catfish IMO will have to be purchased at a really large size to be housed with rtc and tsn. If you get one already 2' and keep it in the large tank seperate until the others are large enough to go in with it you'd be fine, but eventually a few years from now they might get large enough to eat him. There's many catfish that get large enough to house with them, but finding them is the hard part. A planiceps a little larger than them would work well too as they get 5', but are skinny as hell, and all mouth so be carefull.
sadly...
hehe! yeah i agree with the large variety of cats capable of 'growing' and the hardship a fish keeper must endure to at least spot one in lfs. but i think i have connections good enough to get me one. hehehe.
