I have high hopes for this series; I really enjoyed Peter Michaux's "Scheme from Scratch" series, from which the author says gained inspiration for his series:
How does this compare to JSqueak? Does it run Morphic?
It seems to integrate better with the host JVM (like GST integrates with unix).
It's my understanding that JSqueak was (is?) just a toy. OTOH, redline aims to be a full blown implementation of smalltalk that integrates with the jvm like jruby, scala, clojure, etc do. As you can see from the github repo, it's still pretty much a work in progress (plus a learning tutorial for interpreters/compilers).