At first I looked at the Namba gearbag to transport my KPA. But I'm going to transport my KPA at least once a week in a car with a lot of other gear and flightcases so I want something more roadproof. I searched for a case that comes as close as possible with the measures of the KPA. I found one at Musicstore and I think it's very nice and it's price is less than Namba.
KPA: 22X38X18
Rockbag: 25x41x18
Price € 58. I've ordered one at Musicstore