PSI also has them. One thing I have noticed, though, is no one sells them in multiple kit sets, only as individual kit sleeves. The reason is likely that there are just too many tube sizes for anyone to make an affordable set.
I am making my sleeves from PVC blanks for each of the tube sizes I use. There is a good video on Wooden-N-Whimsies web site on how to make a barrel trimming sleeve. Videos | Page 1 of 1. Scroll to the bottom of the page.
a Pen Mill Set. with 4 or 5 different size tube cleraners.
Maybe Woodcraft carries them.