An updated SNAPSHOT was pushed for the $(version) issue.
You should be able to override the internal "jetty.version" now with a system property.
[joakim@lapetus jetty-distribution-7.6.0.v20120127]$ cp ~/.m2/repository/org/eclipse/jetty/jetty-start/7.6.1-SNAPSHOT/jetty-start-7.6.1-SNAPSHOT.jar start.jar
[joakim@lapetus jetty-distribution-7.6.0.v20120127]$ java -Djetty.version=7.6.0.v20120127 -jar start.jar2012-01-30 10:00:20.400:INFO:oejs.Server:jetty-7.6.0.v20120127
2012-01-30 10:00:20.418:INFO:oejdp.ScanningAppProvider:Deployment monitor /home/joakim/code/intalio/distros/jetty-distribution-7.6.0.v20120127/webapps at interval 1
2012-01-30 10:00:20.421:INFO:oejdp.ScanningAppProvider:Deployment monitor /home/joakim/code/intalio/distros/jetty-distribution-7.6.0.v20120127/contexts at interval 1
2012-01-30 10:00:20.423:INFO:oejd.DeploymentManager:Deployable added: /home/joakim/code/intalio/distros/jetty-distribution-7.6.0.v20120127/contexts/javadoc.xml
2012-01-30 10:00:20.448:INFO:oejsh.ContextHandler:started o.e.j.s.h.ContextHandler{/javadoc,file:/home/joakim/code/intalio/distros/jetty-distribution-7.6.0.v20120127/javadoc/}
2012-01-30 10:00:20.449:INFO:oejd.DeploymentManager:Deployable added: /home/joakim/code/intalio/distros/jetty-distribution-7.6.0.v20120127/contexts/test.xml
2012-01-30 10:00:20.484:INFO:oejw.WebInfConfiguration:Extract jar:file:/home/joakim/code/intalio/distros/jetty-distribution-7.6.0.v20120127/webapps/test.war!/ to /tmp/jetty-0.0.0.0-8080-test.war-_-any-/webapp
2012-01-30 10:00:20.868:INFO:oejsh.ContextHandler:started o.e.j.w.WebAppContext{/,file:/tmp/jetty-0.0.0.0-8080-test.war-_-any-/webapp/},/home/joakim/code/intalio/distros/jetty-distribution-7.6.0.v20120127/webapps/test.war
2012-01-30 10:00:22.488:INFO:oejs.Server:Graceful shutdown o.e.j.s.h.ContextHandler{/javadoc,file:/home/joakim/code/intalio/distros/jetty-distribution-7.6.0.v20120127/javadoc/}
2012-01-30 10:00:22.488:INFO:oejs.Server:Graceful shutdown o.e.j.w.WebAppContext{/,file:/tmp/jetty-0.0.0.0-8080-test.war-_-any-/webapp/},/home/joakim/code/intalio/distros/jetty-distribution-7.6.0.v20120127/webapps/test.war
2012-01-30 10:00:23.579:INFO:oejsl.ELContextCleaner:javax.el.BeanELResolver purged
2012-01-30 10:00:23.579:INFO:oejsh.ContextHandler:stopped o.e.j.w.WebAppContext{/,file:/tmp/jetty-0.0.0.0-8080-test.war-_-any-/webapp/},/home/joakim/code/intalio/distros/jetty-distribution-7.6.0.v20120127/webapps/test.war
2012-01-30 10:00:23.584:INFO:oejsh.ContextHandler:stopped o.e.j.s.h.ContextHandler{/javadoc,file:/home/joakim/code/intalio/distros/jetty-distribution-7.6.0.v20120127/javadoc/}
[joakim@