Here is a first attempt to render a doodle from my sketchbook entirely into gimp, I had already experienced some mixed renders analog/digital to achieve result like this http://alex-moreau.blogspot.com/2011/08/phone-case.html and I think that is also an interesting way to work but if you really don’t have time it is really a time saver to render right away in the digital way.

You will find on my blog the original version http://alex-moreau.blogspot.com/2011/08/1st-rendering-test-with-gimp.html