I-Ds can be submitted in PostScript format if that helps,
though a text version (that can be different due to issues
with figures and non-ASCII characters) is still required to
have both published.
Assuming, obviously incorrectly, that the same "simultaneous
posting in text and PS or PDF" principle applied to I-Ds as
well as RFCs, this one was sent to the I-D administrator in
text and pdf formats. The latter was discarded. If we would
like a PDF alternative, I think that is a small matter of the
IESG expanding the rules.
There are currently quite a few PDF files in the internet-drafts
direcories, and I don't think they got there by accident.