I did a nice little toolbox cage holder for my old Kubota that can be adapted to the CK20 for behind the seat.
http://www.tractorbynet.com/forums/customization/104110-l2800-l3400-tool-box-4.html
Will post up some pics next week on what it looks like.
First and second was for Army box the third was for a toolbox that can be lifted out if needed, that is what I liked the most was to be able to lift toolbox out.