...who has an 18Lb tall cat that that stands up to pee, walks right into the box and doesn't turn around, so she needs a box that is high enough to catch the pee, but isn't too high because she has arthritis and she jumps out the side? (Sorry, I know I've posted about her litter box being too small in length & width before. But, I am trying again: current box 19.5"L x 16"W x 8"H - the height being the only purrfect part, and it is the same on all sides.) I went through all of the ones in the recommended list (What's The Largest Cat Litter Box (and Why Your Cat Needs It)), and none will work. They are either too low, or too high, and (NOTE FOR THE STAFF HERE) many of the covered boxes are actually smaller than the listed dimensions, which is the result of the manufacturer listing NOT the size at the bottom of the box, but at the part where the top and bottom connect - on the outside edge. I've researched storage boxes, containers, cement mixing tubs, and I can't even remember what other terms I have used - all to no avail. I have been to at least a dozen different stores... I know some of you have talked about cutting a hole in the front of a plastic storage container - assuming I could even find one even close to the right size (I am still looking for one around 24"L x 21"W - and as close to 8"H as possible). But, I have no idea how to do that, how big of a cut (because of her peeing habits), and what to do with the rough edge resulting from the cut. Please advise me about this. And, are there any other options?? HELP!!!!!!