Exupery is a native code compiler, here's a few references that are have heavily influenced Exupery. Exupery 0.07 is the compiler from Appels book beginning to get the OO optimisations from Urs Hoelzle's thesis.
The first half of "Modern Compiler Implementation in C" by Andrew W. Appel upto and including the chapter on register allocation is what I based the current compiler on.
My view on optimising dynamic object oriented languages is heavily influenced by Urs Hoelzle's thesis which is availible here http://citeseer.ist.psu.edu/hlzle94adaptive.html. This describes how to use dynamic type feedback to remove the OO overhead.