>> : is just a letter character; it's just convention that puts it only  
>> once in the function names. Other package writers may well do odd  
>> things in their naming if they wish :)

Yes, : is a just letter, but it's important when the suffixes
are parsed to generate a new variant.

> Does \module:name:suffix have any advantage over \module_name:suffix ?

The problem with _ is it has two different meanings - namely,
as "space" in names and as module separator. Either the first
_ is *always* a module separator, or a different character
should be used. Having the module clearly differentiated is
more consistent and allows for future refinements.

Javier