I'm in the same boat with my 2x2x2 cube. I'm loving how it's filling in, but it also means I'm stuck....I can't add anything else, and that always gets a little boring.
Granted, I lose A LOT of space to my massive killer elegance, but I can't bring myself to part with it....I've had it seven years. I'm starting to make use of the glass in my tank to squeeze a little more in. I just glued a pink/green pocillopora to my overflow, and frag-mags have become my new best friend, they don't stand out as much as racks and they're easy to move around.
If anything, it looks like you may be able to go "up" another level? I brought my rock up pretty close to the top of the tank. So close that one of my birdsnests is out of the water.
Not to hijak, but here is my 60 cube.
I think I'm going to move the MP10 on the back wall to the other side, and put in a few montipora colonies to let them fill that area in a bit. There's nothing down below so it's not a big deal if they shade that corner.
I'll trade you my elegance for your clam
