The Oberon system introduces a mechanism called Slim Binaries at
http://caesar.ics.uci.edu/oberon/research.html#SlimBinaries
It is a way to store optimized machine-independent code in such a way that loading can convert it to machine code while loading. Due to the compactness of the represenation, loading times (from mass storage or networks) is actually extremely good, compensating for the extra CPU effort required to generate real code on the fly.
It's also a perfect way to define a portable "almost-executable" s/w format. See Juice [L1 ] and Mobile Code for Intrusion Tolerant Systems [L2 ].
Michael Franz's home page the inventor of Slim Binaries [L3 ].