Update: based on comments here and on other forums, I ordered a Remora holster (the 8R-UC to be precise). First impressions:
1. The outside is rubberized and is considerably 'stickier' than other pocket holsters I looked at before ordering.
2. The inside is lined with a barely-padded synthetic fabric (nylon?). There was an option to line the interior with leather, and if I were ordering another, I would probably do this for a smidge less bulk.
3. That said, the holster doesn't add much bulk. LCR pocket carry in jeans is comfortable, and concealable. But just barely, in typical jeans pockets; in pants with deeper pockets it's easy.
4. The Remora holster is sticky enough that IWB appendix carry works on friction alone. Not sure if I would trust it not *ever* to slip, but I would trust it for low-intensity activity with unstretchy material (i.e., not sweatpants). I have read reports of others carrying IWB this way. Haven't tried it myself outside the house yet.