Have a look at
the Singapore Library. It is for free and does have epub and mobi books to lend. They do have 21,813 ebooks and 2,017 are mobis, but have a look yourself.
Maybe you should have a look at other ebook readers than the nook or the Kindle. There are wonderful options out there,
the Bookeen Orizon i.e. or
the BeBook Neo or
the iRiver Cover Story.
All of them have wifi and read epub, have touchscreens, take notes, read a lot of other formats, play audiofiles...