I hate it when I dont learn from my bad experience...
When I have a solution with a web part and I want to add another web part to the same project I just right click the project, select "Add" and choose "Class". Then I tell the class to inherit from "WebPart" and proceed to program my code.
And when I get to deploying it - the new class isnt shown in the new webparts gallery!
because I forget every time to mark the class as "public" - when Visual Studio creates a new class in a project, the default is just "class newwebpart".
So the lesson for today - dont beat yourself going over the web.config file - just make sure the class is marked public.