[userbinator]

used only environment variables with embedded characters which couldn't easily be created by normal means

    SOMEVAR="`cat some_binary_file`"

[mzs]

No not like that, something more like this:

()SOMEVAR@%=...

You will get a parse error. There is little more than [a-zA-Z0-9_] you can use in identifiers (except bash adds a few more, grrrr). You can probably pull it of with /usr/bin/env though.