I have absolutely no clue what they look like but I saw an ad for one on predatory fish keepers from one of there vendors and was interested but they didn't have pics of it up.
Several members on here have owned them. Do some searching here in the catfish section and you'll find the pics. There are also hybrid catfish threads with pics of them. I assume from the hybrids I've raised that you can expect it to be intermediate in size between the two species as an adult. I would say probably 3-4.5' max as an adult.
i got a pair from my LFS hope. shape of a niger, mouth size of a niger, sports of a TSN swims around like a TSN hope they wont be like a TNS and start eating my gars up =)