Homemade litter boxes for corners?

So we were having a litter training issues (getting a little better) and I have small kitten litter boxes in the house in corners, but our one girl poops next to them or in the "corner" that putting them in the corner makes... its like you fix one corner and it makes 2 more potential corners.

Anyway, husband wants to make corner litter boxes because we felt that $15/ea was too expensive.

Has anyone made their own corner boxes? How well did they work out, what materials did you  use? 

Thanks!

 I have pickup rectangle cat litter boxes for about 3.00 - 5.00  (9 1/2 x 13). (wal-mart, general dollar store or dollar store). 

If your rectangular boxes are deep, try cutting down one side where they go in and out.  It's my opinion that they like to see in front of them when they go.  This has helped us some.

THE DOOKS OF HAZARD

I was thinking of using a cardboard box... like the ones used for short tomato sauce cans or vienna sausages...

I don't see why you'd have any more problems with homemade ones than store bought boxes, depending on the material.
To keep it simple, i recommend you cut up some plastic storage bins, be sure to sand or file the edges so the carpet sharks don't get cut! Stay away from absorbent materials such as wood or cardboard, they can soak up some of the smell. 

Cardboard strictly for disposable pan... as it would definitely soak up stink. Maybe like a disposable aluminum baking pan. It could be cut down slightly and rolled to prevent cutting the fuzzies. I wouldnt waste a storage bin to chop it up and make a litter pan.