Free cursor movement beyond the end of line

[yegupov@gmail.com]

Hello. 

There is popular text editors option "allow cursor movement end of line". 
It was implemented in many of text editors long time ago.

But it seems that it's absent in emacs (yes, I tried set-goal-column, picture-mode, artist-mode).


For example when I edit the text: 
------------------------------
this is my long line|
short line
this is my other long line
------------------------------

What I need: 

 - when press "down" key cursor should keep position at column 21:
------------------------------
this is my long line
short line          |
this is my other long line
------------------------------

 - buffer shouldn't be modified because of cursor movement only, no need to surprising trailing spaces; 

 - keys like C-e should move cursor to the REAL end of line:
------------------------------
this is my long line
short line|
this is my other long line
------------------------------
 - this should be worked ok with visual-line-mode mode too


Notes 
 - set-goal-column seems a something close about that but not exactly
 - artist-mode and picture-mode unfortunatelly add extra spaces and has surprice behavour in visual-line-mode


Is there a way to solve somehow this problem in emacs?