anyone using XULRunner on build.eclipse.org (e.g. for testing), as of bug 287505, there's now new common XULRunner library available under /shared/common/mozilla-xulrunner181-1.8.1.4-30.ppc/
Feel free to use it!
For example to enable it in Athena CBI put following in testing.properties extraVMargs=-Dorg.eclipse.swt.browser.XULRunnerPath=/shared/common/mozilla-xulrunner181-1.8.1.4-30.ppc
btw. there's also work going on towards creating Eclipse update site for XULRunner 1.9 on Mozilla.org If you're interested, speak up in bug https://bugzilla.mozilla.org/show_bug.cgi?id=507575
(So far there was only 1.8.1 update site there, but that's really old stuff, no?)