If I may make a logo suggestion: as my fellow Canadian @Geek1011 knows, Kobo is headquartered in Toronto. From 1942 to 1963, the Canadian nickel (five-cent coin) wasn't round, but instead was a regular dodecagon (a 12-sided polygon):
https://en.wikipedia.org/wiki/Dodecagon
So, how about a dodecagon outline with three horizontal lines (a hamburger menu) within it? This would fit in with the current Kobo icon style (including the "brightness" sun, "settings" gear, and "search" magnifying glass), and:
(1) honour Kobo's origins;
(2) acknowledge geek1011's creation of NickelMenu; and
(3) be "read" as exactly what it represents: "nickel menu."
I'm no artist, and the outline lines should probably be thicker, but something like this:
My two -- ur, FIVE -- cents' worth.
Rob