Hey now! That is a good idea! I suppose I would have to fix the loop of the pipe outside the tank extremely well to the wall to make sure the water level doesn't change there and cause a problem, but that sounds good. I think I might try that one out on my 90g, or the 180g later on seeing as though I've already epoxied the tube together.
I am worried that it might overflow though. I think I might just add another overflow onto the 55g like the one you posted for insurance. If one gets clogged the other underwater probably won't be.
I think I'll also add an alarm. I think I can easily make one with parts from radio shack that will let me know if the tank is overflowing.
Something like this