I'm trying to customise my Blender further, but finding it hard to set it up the way I want.
A few of the things I want to accomplish in order of complexity:

Box select on <kbd>LMB ![LMB][L]</kbd>  
Box select with consistent modifier-key use: <kbd>Shift</kbd> <kbd>LMB ![LMB][L]</kbd> to add to selection, <kbd>Ctrl</kbd> <kbd>LMB ![LMB][L]</kbd> to remove from selection.  
The above, but additionally: releasing the <kbd>LMB ![LMB][L]</kbd> exits box select (confirms)  
The above, but additionally: clicking over empty viewport starts box select, clicking over a mesh starts paint-select.

I know I can set Box Select to <kbd>LMB ![LMB][L]</kbd> click, but have found it kind of annoying without at least some of the other things I bring up. Are these possible, and if so: without much scripting?

[L]: https://wiki.blender.org/uploads/1/10/Template-LMB.png