There's a long running thread here:
https://www.mobileread.com/forums/showthread.php?t=82160 but I haven't seen anything I'd pay money for. I'm using the modified DVD case when I take it somewhere, but find it comfortable by itself for reading.
I do like the Kobo store, but I prefer the epubs instead of the direct download. I
will check out the new app when it is released.