I also am looking for a PCSB-sized hybrid bag/cube with (detachable strap and) "exterior" fabric: Halcyon 400d, 525d ballistic, and/or 630d recycled....
For what it's worth, there have been several threads recently about using an S25 or an SN30 as a personal item. Following up on your "squish it down"...
Looks like that is a "yes". The cube in question is almost identical to a WF small: 11.8 x 9.1 x 3.5 inches (vs WF S being 11.8 x 8.7 x 3.1 inches)....
I expect mine to be less of an organizer and more a daily journal/diary with occasional long posts (taking notes on a finished book, for example). A...
A dark-colored PCSB-sized shoulder bag in a non-black dark color. Adding a dark 210d ballistic color would do it, as would making a PCSB-sized bag in...