One thing I don't like is the initialization of boost::flyweight: http://svn.boost.org/svn/boost/sandbox/flyweight/libs/flyweight/doc/tutorial... I think there could be a simpler way to do this: http://www.entropygames.net/globals.htm
Well, static_holder (which is conceptually very similar to a singleton) does in fact relies on Meyers' idiom, all the complications described at the referred section stems from the fact that initialization is forced to happen in pre-main() time to avoid multi-threaded clashes (which are deemed more unlikely before than after main() starts). Note that the singletons described at your article can pose problems if first accessed simultaneously from two different threads --this is what I tried to avoid in my lib.
I was talking about depends_on class Best, John -- http://John.Torjo.com -- C++ expert ... call me only if you want things done right