I really like the way the SysInternals utilities (e.g. Process Explorer) handle 64bit compatibility. It looks like the 32bit executable has the 64bit version embedded in it, and extracts it if necessary.
I'd like a tool which automates this - i.e. takes 32bit and 64bit executables, packs them together somehow, and inserts stub code to launch the right executable according to which platform its gets run on.
Before I start to roll my own, does anyone know of something like this which already exists?
Mark Russinovich of SysInternals fame describes their method here. They do embed an x64 image in an x86 image. Unfortunately above blog post doesn't actually go into too much detail but mentions that their technique is based on a much older article found here.