Any source for Shimano shoelaces?
I don't think that the exact laces are available under the Shimano brand, but the internet may prove me wrong.

The closest thing I have found online is oval athletic laces like these: 



When I replaced mine I found similar laces at a sporting goods store, but I've seen similar sport laces at some of the big box stores as well. If you google "oval athletic laces" you should find a large number of online sellers as well.