I added two penloop-cards from a slim-sized Flex (one had to be cut a bit smaller) - et voila: I now have 4 penloops!
Unfortunately (and I didn't mention this in the video), I have meanwhile received my A5 Chameleon and the penloop hack is useless here because of the different pocket arrangement. Plus, the penloops in the Chameleon are soooo tight! I bought a second Slim Frixion (in matte black - very very chique!), and I just stuff the other two Frixions in the zipper. Okay for now, but will need to improve that for the future!
Without further ado, here's the link to the video!