I am doing looking for the same comportment than you. Actualy here is how i do using "display:table" (and not "float").
The xhtml :
<div id="main">
<div class="left_collumn">
<div class="breadcrumbs">[!Breadcrumbs?!]</div>
<quickedit:pagetitle/>
<div class="longtitle">[*#longtitle*]</div>
<div class="introtext">[*#introtext*]</div>
<div class="content">[*#content*]</div>
</div>
<div class="right_collumn">
<h3>Lorem ipsum</h3>
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Sed et libero.....</p>
</div>
</div>
</div>
and an extract of the css :
body {
min-width: 800px;
}
#main {
width: 90%; /* for empty margins */
max-width: 900px;
display: table;
}
.left_collumn {
display: table-cell;
height: 100%; /* the liquid column */
}
.right_collumn {
display: table-cell;
height: 100%;
width: 176px; /* the fixed collumn */
}
This mostly work for Firefox. I did not have tested other brownser yet (i hope it’s not too bugy). The main layout problem is than, if the content of the left block is larger than [(min-width)-(right_collumn-width)] the the output is not correct anymore (too big images for Ex.).
Edit : Argh apparently Explorer 7 and before did not recognise display:table & display:table-cell

Sorry this is defenitly not the good solution.