It’s still buggy and missing a lot of features, but as of revision 469 check out the following:

$ melange --replace &
$ /usr/local/share/screenlets/SidebarUA/SidebarScreenlet.py &

$ /usr/local/share/screenlets/Meter/MeterScreenlet.py --server=Sidebar
$ /usr/local/share/screenlets/DigiClock/DigiClockScreenlet.py --server=Sidebar

Also, drop me a comment if you know of any out-of-branch screenlets whose authors haven’t been contacted yet.