I think I get what you're saying about making sure the pipe is high enough for the water level. That was one of my thoughts. Drilling a couple of holes below the waterline and putting in bulkheads with some type of prefilters. Then on the outside,having the pipe go up to the waterline and then horseshoes around so that the water overflows in the pipe, but outside of the tank. And drilling a couple of small holes in the top most part the of pipe to prevent a siphon.
Another thought was drilling the holes below the waterline and then run the pipe inside the tank to the waterline and let water overflow into that, but then I'd would need to be a really big pipe or I'd get that sucking sound. With a big big I might as well have the overflow.
Then the last thought was to have the holes at the waterline and use that to control that water level, but then it seems like the water line would be lower than the top of the tank and I'd get that white calcium water line over time.
I did see a tank that had about 1/2 maybe 3/4's of an inch of glass remove from the top of the back glass. The water would spill over that into and external overflow box and then drain into the sump. Seems like a good idea, but it would be a PITA to recreate it.