Bootstrap: how to extend input to occupy available space?

Bootstrap: how to extend input to occupy available space?

I created this example: jsFiddle
<div class="container">
<div class="row">
<div class="span6">
<ul class="thumbnails">
<li class="span4">
<div style="height:200px; position: relative" class="thumbnail">
<div style="position: absolute; left: 5px; right: 5px;
bottom:5px;">
<form style="margin:0;" class="form-inline">
<input style="margin: 3px 0 0 0;" type="text"
placeholder="Name…" ng-model="mashName"
class="pull-left span3" />
<button type="submit" style="margin: 3px 0 0 0; "
class="span1 btn btn-primary
pull-right">Create</button>
</form>
</div>
</div>
</li>
</ul>
</div>
What I need is for the input to extend to the button, without using
percentages that screw everything when resizing. This example is very
near, but the button is screwed by using span..
.input-block-level is nice, but it extends all the way.. instead it should
stop just before the button. is there a way to fix this without
javascript?