Although not much advertised, Kobo Glo supports .mobi format of ebooks. Mobi is also known as MobiPocket Reader format and is usually used for older or DRM protected ebooks.
I have tested the Mobi support of Kobo Glo and it works flawlessly. You can directly transfer your .mobi ebooks (similarly to .epub) to your Kobo Glo or use software such as Calibre or others.
In case, you encounter a Kobo Glo device not supporting .mobi, let me know the details from the Settings->Device Information.
My Kobo Glo Device information with Mobi support:
- Software version: 2.8.1 (20th of Sept., 2013)
As you can see, the firmware is pretty recent as of writing this blog post (just two months old).