I am familiar with the pen tray liners sold by gopens.com, and they work very well for skinny to medium pens. For fatter pens, though, not so great, the pens are too large to nestle into the curved space provided, and although they can sit that way and be fairly stable, you can't have anything next to them on either side, which really eats up storage space. 15 mm seems to be the largest girth in a pen that fits comfortably in those trays.
I found some long and fairly narrow jewelry trays of a similar material (flocked plastic) but they are both rather flimsy and wider than they need to be (24 mm at the bottom, where 20 mm should be plenty). So I'm looking for pen tray liners that have spaces that are about 20 mm or 3/4" wide and preferably under 1/2" deep.
Any leads or suggestions?