Not all babies have an odor. I've researched it because I was concerned at first but it seems that a lot of stumps that don't get swabbed with alcohol develop an odor. An odor can also be a sign of infection but stump infections are rare and aside from the smell it's healing nicely. I'm going to give it a few days to fall off (it's so close!) and once it falls off the smell should go away, if not i'll call the doctor.
I've heard of people saving the stump, and sarah, while what you said was beautiful, I don't think I could save it. I'm so grossed out by it!