extending <a> elements to extend gradient nav bar to end of page - html

Question

I'm creating a site with a horizontal navbar in which the buttons are designed as elements, making them easy to differentiate, and they individually light up when you a:hover over them. Here's a link: http://allpropestmanagement.net/commercial2.html
Obviously not a finished product.
My current problem involves that big purple field on the far right of the navbar, the one that's not a button. That too is an element, but with hover disabled and a whole load of nonbreaking spaces to pad it. That's the problem. I would like that purple field to extend all the way to the right end (with a tiny margin, like it does on the left side). The trouble with nbsp, as you can imagine, is that there's a finite number of them, and they don't scale. So if the navbar is the perfect length on my computer with, say, 16 nbsps, on someone else's machine it won't reach all the way and on yet another person's it will reach too far.
The html looks like this:
<div id="navmenu">
<form>
Home
Commercial
Meet The Pro
Contact
<a id="farright" style="border-top-right-radius:25px;">
<i> "We'll get the job done right!"
</i></a>
</form>
</div>
I feel odd saying this, but the css is kind of bulky and I'm having trouble formatting this post. Perhaps I'll add it in a few minutes once this post is visible, but the css file is "smithmicropurple.css".
Anyway, I would like a way to stretch that element so it always fits correctly, or if not, some other method that achieves the same effect. I have already tried setting widths individually for each element and that doesn't appear to work.

Answer 1

I like to do these types of things to "help" others (rarely, if I'm lucky), but also to help me learn more about html/css.
So I've given it the old college try with this FIDDLE.
HTML
<div class='holderdiv'>
<a href='#'>One</a>
<a href='#'>Two</a>
<a href='#'>Three</a>
<a href='#'>Four</a>
<a href='#'>We'll Get the Job Done Right!</a>
</div>
I won't post the CSS because it's pretty long. It's in the fiddle.
Please don't consider this a "real" answer. Perhaps just something to think about.

Answer 2

Semantically, I am not sure why the parent is a form element, i'd suggest changing that to a HTML5 <nav> element. (assuming you're using HTML5, of course)
The approach taken here is to set the child elements to display:table-cell, and give the targeted element, #farright a width of 100% to fill the remaining space. Also, text-align:center will effectively center all the child elements. No need for %nbsp;
#navmenu {
font-size: 14pt;
margin: 5px 0 0 5px;
}
#navmenu form {
width: 940px;
}
#navmenu form > a {
display: table-cell;
white-space: nowrap;
text-align:center;
}
#navmenu #farright {
width:100%;
}