Can Anaconda be packaged for a portable zero-configuration install?

Since you mentioned WinPython as an option, but said you dismissed it for being 'too large':

WinPython now includes a 'Zero' version with each release that has nearly all of the bloat removed (equivalent to the relationship between Miniconda and Anaconda). I believe the folder containing the WinPython-64bit v3.6.3.0Zero release clocked in around 50-100MB.

You can use the silent install mode to create a fully portable Miniconda install (250MB for v.4.3.21 windows x64).

Miniconda3-latest-Windows-x86_64.exe /InstallationType=JustMe /AddToPath=0 /RegisterPython=0 /NoRegistry=1

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