I had a Zagg for my android phone and while it was ridiculously tough, the glue dried up after 2 months.
For the Kobo, look into the laptop screen protectors, then just cut it to fit. They come with a protective backing (like a sticker) so you can test fit it before you actually stick it on.
http://www.bestskinsever.com/
That's where I get my skins from now. They already make skins for the kindle and playbook, so maybe Kobo is coming up soon?
edit:
http://www.bestskinsever.com/diy-skins
There