I'll try to get some pictures posted soon.
I checked the stats for the PW carefully in the hope that my it would fit into the Oberon Touch Cover. I saw that the PW was one tenth of an inch smaller in each dimension (I'm not sure about thickness), so I went ahead figuring that this was pretty close. Unaltered, the PW has a bit of wiggle room, which makes me wonder about all the older cases now advertised to fit either the touch or the paperwhite. Anyway, putting some felt strips for filler inside the big pocket behind the PW will work also, but it's not as effective, and not nearly as elegant.
Gluing the felt to the underside of the three leather corner retaining straps makes for a perfect fit, is almost invisible (the felt, the straps and the PW are all black), and the PW is actually easier to get into and out of the cover than the Touch. (I think because the felt gives a little, but I'm not sure. Also, with the PW, I slide it into the two corners on the left, then force the third strap over the bottom right corner - then finish with the elastic. Note that even the Oberon people struggle a little getting the Touch device into the case on their videos.)
Finally, Oberon notes that the extra space around the edge of the cover gives extra protection against mishaps on the side - that space is now 0.1 inch greater, and every little bit helps.
I went slow, and cutting the felt and gluing it to the bottom of the straps took about fifteen minutes.
Considering that these are surely the best, but pricy, cases available, I think this is a nice way to keep the cover when upgrading. I looked for a place to post this info on the Oberon site, but could not find one.