There are some great new regarding the jQuery UI Selectmenu widget!
It's official: the new, built from scratch version of Selectmenu is planned to be released with jQuery UI 1.10 (hopefully January 2013).
Besides, I've released a new version of my jQuery UI selectmenu fork. This release includes mainly bugfixes, a few minor feature requests and is compatible with jQuery 1.8 (now using jQuery 1.8.2 / UI 1.8.24) . See here for full list of all solved issues.
Thanks to all contributors for making this possible!
Please consider an donation to support my work on this effort.