There's new version of the self-bootstrapping environment for Squeak 3.9-7033.
Download: http://www.comtalk.net/Squeak/uploads/20/bootstrap7033c.zip

Finally the resultant image contains no obsolete classes... ufff...
:-) Some references were really hard to find and destroy if you can
work only with console. I have also removed many unsent messages
automatically.

You may use "MirrorsBrowser open" for mirrors browsing.

Some statical data:
Smalltalk allClassesAndTraits -> 476
CompiledMethod allInstances size -> 10962
Image size: 3,2 MB

System categories:
Kernel-Chronology
Kernel-Classes
Kernel-Contexts
Kernel-Methods
Kernel-Numbers
Kernel-Objects
Kernel-Processes
Collections-Abstract
Collections-Arrayed
Collections-Sequenceable
Collections-SkipLists
Collections-Streams
Collections-Strings
Collections-Support
Collections-Text
Collections-Unordered
Collections-Weak
Collections-Stack
Exceptions-Kernel
Exceptions-Extensions
Exceptions-Tests
Files-Kernel
Files-Directories
Files-System
Graphics-Display Objects
Graphics-Primitives
Graphics-Text
Graphics-Transformations
Graphics-Fonts
Multilingual-Display
Multilingual-Encodings
Multilingual-ImmPlugin
Multilingual-Languages
Multilingual-Scanning
Multilingual-TextConversion
Protocols-Kernel
ST80-Kernel-Remnants
ST80-Support
Compiler-Kernel
Compiler-ParseNodes
Compiler-Support
System-Change Notification
System-Finalization
System-Localization
System-Object Events
System-Object Events-Tests
System-Object Storage
System-Pools
System-Support
System-FileRegistry
System-Changes
System-Tools
Tools-Changes
ToolBuilder-Kernel
Traits-System Change Notification
Traits-Kernel
Traits-Kernel-Traits
Traits-Composition
Traits-Requires
Traits-LocalSends

SqueakSource repository (http://www.squeaksource.com/KernelImage.html)
is still not working well but you can use "Bootstrap new
fileOutMirrors" for sharing whole mirrors world.

-- Pavel