crazzy: Don't really know yet. I usually supersize things but it's important to keep in mind that the standard off-the-shelf wave box will generate 15,000 gph on an 8' tank.
It's also very important to note that Tunze does not recommend using the wave box as a sole means of flow, and they strongy recommend that the tank be built out of panes that are one size up from standard to take the wave motion.
The pump that comes in the wavebox can be ordered through Roger, but other pumps can be used as well. The 6201 would be good, or even the 6301 for massive flow. Hiding the wavebox takes care fo some of the downside of using Tunze because they will not be visible at all.
As far as sizing my experimental one, I will probably make it abou t2 - 3 times the size of a standard wavebox. This will give ma a longer flow time. As you might know, I am not entirely convinced that making waves is the best flow for our captive tanks. It is the current "IN" thing, but I would rather have very high alternating and controllable currents, rather than a wave. I was hoping to get this with the Vortech line but that doesn't seem to be working out.
And BTW, I will also build an external wavebox for a Vortech just to see what it can do. I have a 90g just laying around that I will experiment with. I believe the same idea can be applied to the Vortech with a clever external box.