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).
Offical jQuery UI Selectmenu
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!
jQuery UI Selectemenu fork
Please consider an donation to support my work on this effort.