There has been a call from within the Common Lisp community to work toward consolidating libraries. http://fare.livejournal.com/169346.html
I think this is a step in the right direction. If the XKCD comic is true that every generation produces a handful of lisp hackers, I hope this is the generation that looks to Quicklisp as a foundation to build a modern, consolidated set of batteries.
Check out the list of EIGHT GTK+ bindings for Common Lisp: http://www.cliki.net/GTK%20binding
And yet, the last time I attempted to write a trivial GUI application using GTK and CL, I could not find a single usable library. I tried four and they were all unusably broken on my platform. (This was some years ago. Clearly at least four more implementations have come around since then.)