I always assumed there are a company in china putting prints on their otherwise standard selection of diapers.
There are (cheaper) plain versions of the expensive print ones targetted at the ABDL market.
I don't see the need for print on the diapers - there are plastic pants or snap on pants or pull up covers that can have any number of patterns on or add bulk. The pattern then providing cute etc.
From a fetish perspective in the UK I quite like diapers from a company called Gompels Healthcare.
They were plastic backed, tapes were crappy, absorbancy was OK. Terribly noisy. Fetish wise that worked for me just fine :)
Incontinence wise. Better Dry.
It seems you can pee in them all day and they just don't leak.