I've yet to run into a menu I can't use the mouse in. Have you considered clicking on things before saying they don't work? Dragging them? Maybe trying them twice in case you missed them the first time? Even the "ENTER Accept TAB Exit" buttons work through the mouse when you click on them. The only thing I'd like to see a mod fix is the spacing - maybe make the text smaller, too.
Theres clearly an issue SOME people have with mouse in menus. I cant click on [censored]. Character creation broke for me if I used the mouse to change the angle of the character's face, as i couldnt click back into the menus.
Clearly this isn't an issue everyone has. This being said, my computer is high end with solid hardware, the latest OS, etc, so whatever the cause of this is, there's clearly some bug to squash. And believe me, I tried dozens of time.
Glad to know the problem isnt universal though.
EDIT: On a related note, I managed to both eliminate random 'mouse lag' and -somewhat- improve mouse usability in general by disabling vsync thusly:
"add iPresentInterval=0 to the bottom of the [Display] section of the Skyrim.ini file in the \Users\[Username]\My Documents\My Games\Skyrim directory."