danw,
I'm a huge fan of using a sump, although it's not absolutely necessary in all cases.
If you want one - make one.
A 10 gallon or 15 gallon glass tank will work fine, if it will fit under the stand. That's where most folks place them.
A plastic rubbermaid container will work too.
You'll need the the actual sump itself.
You'll need an external hang on the back overflow.
You'll need a return pump.
You'll need a drain hose from the overflow to the sump.
You'll need some vinyl hose to run from the return pump up to the display tank.
You'll need pvc fittings/adaptors to hook everything up.
Some hose clamps and pvc primer & glue.
You'll need some sort of spraybar - either DIY or store bought.
A Lifereef overflow rated at 700 gph would be fine.
Their boxes come with siphon tube(s), foam filter element(s), hose clamps, and 1" vinyl tubing hosebarb.
Single prefilter/skimmer box: $89.00 bucks
A Magdrive 7 would give you around 500 gph $50.00 bucks
You already have the sump
Vinyl tubing, clamps - Home Depot or Lowes - $20.00 bucks
Spraybar - buy one $10.00 bucks or make your own - again Home Depot/Lowes $10.00 bucks or so.
That's about it for a plain ole sump system - figure between $175.00 to $200.00 bucks if DIY
If you want to add baffles to the sump, or get fancy - you can expect a little more cash needed.
Easy to build - adds water volume to the system - get's the junk out of sight - and increases circulation.
Sumps are great !