Hint: If you're stuck for something to publish and present at an OO conference, just reimplement something done in previous decades with CLOS/Lisp or Smalltalk in a newer 'hipper' language. This is only a half-joke. This actually works!
Well, CLOS does not lend itself to "powerful object oriented design" if you define "powerful object oriented design" as "whatever architecture astronautics is done by Java and .NET programmers", which is exactly what that phrase evokes for me.
http://en.wikipedia.org/wiki/Common_Lisp_Object_System
There is also Arc, the language Paul Graham and Robert Morris wrote for the web. This site is written it it.
http://arclanguage.org/