Macintosh Common Lisp is another one. It was so much fun to use and worked so well with MacOS. Echoing etchalon's comment, sometimes I miss OS 8 (also 9).
No, it had its own - at least in the 'released' technology preview. The Dylan Interface Builder was written in Dylan itself and was loaded directly into the running Dylan application. The Apple Dylan IDE itself was running as a separate MCL application. You can see from the screenshots that the IB also had a different look&feel.