This is truly the knitting bag of my dreams!  And to think I made it myself makes it even sweeter!
It's a kit from Babylon leather.  Everything you need comes in the kit and the materials are quality!  Top grain cowhide and full grain cowhide leather.  There is a video tutorial with each kit and online support if needed.  
I ended up spreading everything out on my dining room table and working on it a little bit of a time.  I think that was the right way to approach it.  That way it wasn't too overwhelming.  
I worked on it a little in the morning.  A little in the afternoon.   A little in the evening.  Just whenever I had a few moments.  The pinholes make it very easy.  As well as the heavy thread and needles.  
I ended up using it while in New York in August.  And it could not have been a better bag to carry my knitting in during the day.  And use as a purse in the evenings.  
This is the unlined Picotin bag in caramel with the white stitching.  I truly adore it!