>
> If you export this file to PDF (C-c C-e d), babel will evaluate and
> export the file as ascii. However, the ascii file will have the
> undesirable "ORG-LIST-END-MARKER" in it.
> Here is the resulting ascii export:
>

Well, this certainly is an odd problem.  I can confirm that I recreated
the problem locally on export to .tex and .html, but not to .txt.  I had
to make the following changes to your example [1] before the code block
returned any results on export.

To make things stranger the marker does not appear in the results when
`org-export-blocks-preprocess' is run outside of a recursive export, or
when the code block is evaluated interactively.

I am not familiar enough with the list exporting code to know where to
begin looking into this, but since the buffer does return an elisp
string, one easy (though unclean) solution would be to
`replace-regexp-in-string' to manually strip the "ORG-LIST-END-MARKER"s
from the string.

Hope this helps,

Footnotes: 
[1]