Whewwwwww.....got to surfing trying to find an answer on this and it's way later now. The only boxes I have seen were the faux ivory ones Kato made on CD. Those just butted up against and the top fit on without hinges. Will look more later.
FYI......ran across a Kato chat that had taken place in March of this year.....Her production guy was talking and saying his company was turning out 4000 lbs of KatoClay every day and still behind. He said they were planning on another big shipment to go out soon.

Bless you for that, Rosie! I should have searched myself. It was one of those times when my imagination was running away with me and quickly on to something else... you know? LOL! I'm not going to give up on the idea, although it may be *quite* some time before I act on it!

I keep wondering how long it will be before the Kato clay will be in stores....?

Her production manager made mention in the chat that people should call their local craft stores and ask when they were going to get the clay. Then if they didn't know about it, the caller would ask they stock it. That's the trouble I have here.....have several craft stores but no one carries anything new.

There is some great box & hinge construction info in Jacqueline Gikow's book, "Polymer Clay : Creating Functional and Decorative Objects". was running this weekend and not online. If I dig up any links I'll let you know.
Sure would be nice if the folks at Prairiecraft would email us customers with Kato clay updates. I have been waiting patiently for 2 months and have heard nothing, other than when I emailed them.

Thanks, Karen; I'll keep an eye out for that book!