How much extra memory does it take to create a doubly-named function, for example:
PHP Code:
Editor.pageMouseDown = function(eEditor_pageMouseDown 
PHP Code:
Editor.pageMouseDown = function(e
It seems that polluting the GLUT (global lookup) would make performance slower overall.

I'd actually like to test to know. How should I test this?

The advantage to having a named function is it makes debug easier.