Lisp in Lisp with a different default data structure

If anyone has seen someone else do this, please let me know.

I'm a little nervous about posting this because last time I put something I considered "research" I got grilled a bit: http://news.ycombinator.com/item?id=1959896. That being said, it stayed at the top of the arc forum for a few days and nobody said this sucked. Well, I fixed the bug, read what I had to read, and am showing HN that that data structure can be used to build Lisp pretty much from scratch. I'm sure you can do it with other data structures, but have neither seen it done nor know what the performance would be like.