Since the discussion is about toolset and compilers, it's worth noting that 4kb intros on windows platforms are nowadays built using a "compressing linker" called crinkler.
Instead of compressing the binary code of the original executable as data which then gets uncompressed when the real executable is run (in that area, kkrunchy is the state of the art on windows), crinkler produces a compressed executable directly, at linking time.
Instead of compressing the binary code of the original executable as data which then gets uncompressed when the real executable is run (in that area, kkrunchy is the state of the art on windows), crinkler produces a compressed executable directly, at linking time.
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http://www.crinkler.net/
http://www.pouet.net/nfo.php?which=18158&f=none -- description of crinkler's operation
http://www.farbrausch.de/~fg/kkrunchy/ -- kkrunchy, a packer which does a code transformation pass before actually compressing it.