This first one is Harvaard Stoere's (of planetcatfish.com fame) hemiancistrus subviridis breeder tank. All real rocks and natural sand found by him. Quite amazing. Even went so far as to cut some of the rocks to fit flush against the back and sides of the glass. Just amazing.
If I remember correctly, he patterned it after the Rio Orinoco.
This one is also owned by Harvaard. I believe he has a breeding colony of zebra plecos in here, but I am not 100% sure. The second picture shows his filter that covers the intake pipes. The rocks surrounding it are modular and can be removed as one piece.
This one was supposed to resemble the deep of the Rio Xingu.