Duvet Cover Thoughts

I have wanted to revamp my bedding for some time now.  Here are a few covers I found that I like:

Here, here and here (this last link is my favorite!).

However, bedding is expensive!  I was inspired to make my own duvet cover out of two flat sheets by this tutorial.

If I found some flat sheets on sale I could make a beautiful duvet cover, embellished with ruffles, for significantly less money than buying one. 

This may be a bigger undertaking than I realize, but I am excited.  I have found a couple other inspiring tutorials here, here, and here.