Width: the trouble of a fixed width div and a relative width

I ran into this problem multiple times. I want to have a two divs. One on the left side with a fixed width (like 150 px) and one on the right side with a variable width, like (a percentage of) the remaining width. I know there are work arounds for this problem, but it’s never a really easy solution (the best one I could find is the Holy grail by Matthew Levine). It would be much easier if I could use something like this:

..left {
    width : 150px;
}
..right {
    width : fill;    (or width : remainder;)
}

it could be even extended by including a percentage like this:

..left {
    width : 150px;
}
..right {
    width : fill 80%;    (or width: remainder 80%;)
}

I think I wouldn’t be the only one who would like this change to the width tag, since a lot of web pages have a site navigation bar at the left side with a fixed width. 
With this modification, one of the problems of different screenresolutions will be solved by only one line of CSS code(in stead of 278 lines I’m using now, a class I created for this in php).

Does this idea have any chance of being implemented in the CSS recommendations?

- Rik