Here's my suggestion for your 40 gal breeder...
1) take my black overflow and cut/router plastic down to the right width (30~36"). Router/trim it narrower (down to maybe 3~4 inches).
Ideally, we should do a glass-holes type "overflow box with three holes, so we need to put a "back" on the box.
http://glass-holes.com/3000-Overflow-Box-Complete-Kit-gh3000kit.htm
2) drill three holes in back of tank for the "bean animal" overflow. (I have two 1" bulkheads)
3) install my "drain piping" setup
PRICING:
#1: give me $20 for the overflow box plastic (you'll need to buy another piece from Tap Plastics 35" wide by 6" high).
#2: give me $10 ($5 for each bulkhead)
#3: give me give me $20 for material (4 unions, 3 valves, T-fitting & drain piping from tank top to sump)
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You'll have to put in maybe $10~20 for the acrylic glue and the acrylic back panel, I mentioned.
Although, I would have said, you should have gone with a 55 gallon (if you were already going to a 40 gallon breeder). ^_^
As for skimmer, that will depend on how tall your stand is. (assuming you want one of my skimmers).