I am considering getting a standard (4' or 5' long) tank and devoting 1 foot
of it as a sump by creating a dam with a glass sheet I glue into one side.
The idea being the water will overflow off the surface into the sump
section.

I am toying with this idea because -
I can enclose (hide!) the sump section in the custom cabinet I am
building.
I won't need anything hanging on the outside of the tank.
I feel more secure (rugs!) not having a need to pump water outside the
tank.
Simpler, foolproof plumbing.
I'll get more mileage out of a sump pump that won't need to work against
any more than a few inches of head.
I can use a more efficent in sump skimmer design.

Has anyone done this? I've never seen a setup like that.
Any drawbacks I'm overlooking?
Pointers?

Comments, both positive and negative, appreciated.
Thomas Bartkus