A few favorite links to fuel the canal barge fantasies...
The key is to get into the brokerage areas, and then select "Converted Barges" or similar... that gets to the good stuff.
http://www.h2ofrance.com/ http://www.luxe-motor.com/ http://www.bourgogne-marine.com/Home.html
I've heard of folks that have actively sailed the world retiring to this lifestyle. No fog, no navigation worries, fall overboard... just stand up and walk to the edge of the canal!
And to the comment "going no where slowly at great expense", the operational costs are dirt cheap compared to ocean going yachts. A 100' foot converted barge is typically <$10K/yr for maintenance (not counting fuel etc.).
I think canal barges are a "must" chapter for boaters... wouldn't want to spend a lifetime there, but 5 years... absolutely!