Got a little page with a screenshot up at http://gsdock.sourceforge.net
Here it is, a new Dock for Cocoa and GNUstep.
The source and a OS X disk image of an OS X executable are available.
You could DL the source and try to compile under GNUstep, but there are still a couple problems under GNUstep.
Works preety good under OS X/Cocoa though!