Rick Chin made a presentation at the Colorado SolidWorks User Group (some years ago) that made a significant impression on me.  His topic was the "absurdly ideal".  Rick now has recently launched a blog www.absurdlyideal.com - the basic concept is to use a structured approach to developing what is as yet unimagined.

I've applied many of Rick's suggestions to projects that have come my way.  His blog may become a good resource for the general discussion of the process of invention.

In the way of shameless self promotion, here's a copy of a recently released magazine column that hints at some of what Rick advises.  Note that most of the figures in the article are shown as links - click on them to see the animations. http://www.thefabricator.com/article/forceos/3-d-cad-modeling-with-limited-resources