Does anyone know how to create an Event Handler that can generate a specific number each time a document is added to a library? I dont really want to use a workflow as there could be many libraries and also we dont want to use a calculated column.
"specific number"? A unique ID for each document? I'd first take a look at the SharePoint Document ID service. You could write an event receiver that used a SQL table, a SharePoint list or other storage to read and increment a unique id.
