From Mike Garrity, "There was an on again/off again thread on OSG users about

creating subclasses of osg::Array that referenced data
stored an application's internal data structures. I took
a stab at implementing that and ran into a couple of
downcasts in Geometry.cpp. Enclosed is my take at fixing
those along with a simple example of how to do this."

include/osg/Array

@@ -229,6 +229,8 @@ class TemplateArray : public Array, public std::vector<T>
         virtual unsigned int    getTotalDataSize() const { return this->size()*sizeof(T); }
         virtual unsigned int    getNumElements() const { return this->size(); }
 
+        typedef T ElementDataType; // expose T
+
     protected:
     
         virtual ~TemplateArray() {}
@@ -315,6 +317,8 @@ class TemplateIndexArray : public IndexArray, public std::vector<T>
 
         virtual unsigned int    index(unsigned int pos) const { return (*this)[pos]; }
 
+        typedef T ElementDataType; // expose T
+
     protected:
     
         virtual ~TemplateIndexArray() {}