Blastwave (name to change soon) is an in-development client for XMMS2 written in C/GTK2. In its current state it features basic XMMS2 control: playlist managing, playback queues (experimental), playback control, MediaLib queries as well as a usable GTK2 interface with tray icon support. Note: the client is work in progress and is currently alpha-stage, so expect odd behaviour:)
You can download the code from the sourceforge.net SVN repository:
$ svn co https://blastwave.svn.sourceforge.net/svnroot/blastwave/tags/blastwave-0-1 blastwave (Version 0.1)
$ svn co https://blastwave.svn.sourceforge.net/svnroot/blastwave/trunk blastwave (Development version)
As for now, Blastwave uses XMMS2-DrJekyll, but it's being developed around latest xmms2 git code.