new Cog VMs are available, SimpleStackBasedCogit @ http://www.mirandabanda.org/files/Cog/VM/VM.r2359/ and StackToRegisterMappingCogit @ http://www.mirandabanda.org/files/Cog/VM/VM.r2361.  I think the new code generator is ready for prime time now.  I fixed a number of bugs over the past three weeks and we're now using the StackToRegisterMappingCogit internally at Teleplace.  There's still work to be done merging plugins and details with the standard VMs  but I hope that r2361 is production-ready as far as core Smalltalk execution is concerned.

Enjoy.

Eliot