Hi Folks,
Just got a new Kindle 3G/Wi-Fi and decided to hack together my own cover. It ran me about $10 for parts and took me about 2 hrs (though I'm not very crafty and it could be much quicker for folks with more skillz). So far, it's been working great--the Kindle is secure, the cover folds back nicely, and the hard cover has protected it well during the day.
I posted it to Instructables, but I'll include some pictures below.
http://www.instructables.com/id/DIY-Kindle-Cover/
Please feel free to let me know what you think might work better in future iterations. I'd like to figure out how to do one that has a reading light built in, but this will take some planning.
Read on,
djulian