I think the original suggestion is a great idea. Came to the very same conclusion today. Evernote holds all the really useful bits of data, the nodes, but a module to play with the relationships between them, and visualise them would be awesome. I'd pay money for that. One of the barriers for people wanting to explore the concept of Mind Maps is creating the nodes. You may have a hundred ideas in your head but only 5 or so pop to mind at a single time. Evernote contains all those nodes already. As your database grows and contains ever more information, the ability to represent that data in different ways is invaluable. A mind-mapping overlay would be gold.