First, I agree with Jim. I think removing the feature entirely until it can be properly addressed is appropriate.

This works fine in CSS:

a[href $='.txt'] {
padding: 0 20px 0 0;
background: transparent url(images/icons/file-txt.png.xhtml) no-repeat
center right;
}

Notice the relative reference-URL. This allows resource loading from any source, as long as you can "do the math" and calculate the relative URL.

However, on side note...

On Fri, 2009-10-02 at 14:39 -0700, Jim Driscoll wrote:

but once we allow it,
we can't "unallow" it when a better method comes along.

I disagree. I think that backwards compatibility has pluses and minuses, but we should not rule out removing features that don't make sense anymore, or changing features that break something in order to achieve a greater good for the future of JSF. It should be done sparingly, but is sometimes necessary.

--
Lincoln Baxter, III
Co-Founder of OcpSoft

Creator of:
PrettyFaces: URL rewriting for JSF
PrettyTime: Java elapsed timestamp formatting