This is something I haven't seen enough of... Boxes for the larger pens. I took an El Grande into Woodcraft just the other day. They had exactly one box it would fit in... The lift of all things!
They also had paper boxes that it was able to squeeze into. I picked up some of those as well just to have in an emergency.
In answer to your question, I have not seen one large enough for 2 Jr's personally. You can get leather pouches for 'em though.