This is an answer to gnd567's thread from February (now closed)
The fact that adult sized plastic potties are not routinely available in the US or UK is not the end of the story. There are other places where they are on sale.
For example: if you run
nocnik dla doroslych
through Google, you will find a Polish company called Jantar who are making them. They are not quite like modern baby potties - more like the old-fashioned under-the-bed chamber pot to look at. But they are not like the institutional hospital commode chairs: you have to squat onto them like a toddler would. They're about 11cm (4-5 inches) tall, and 22cm (9 inches) across, and the fact they are flat (no splash guard) should help. They're white plastic (ideal for potty training stickers when toddlers are good!)
Below Jantar's listing are several Polish distributors who will sell them, and I think they will do international delivery. Price is about 23 Polish zloty - about 8 US bucks or 5 British pounds.
Worth a thought, if that's the sort of AB you are...?