Inline markup status

Hi,

I would like to ask about the current status of the inline markup feature.
I'm aware of the reported state here:
http://docutils.sourceforge.net/FAQ.html#is-nested-inline-markup-possible
but I'm also curious because it doesn't mention the effort described here:
https://sourceforge.net/p/docutils/feature-requests/22/ which seems to have
gotten quite far. However, the patch doesn't apply against the current tree.

For my purposes, it would suffice if we could have one level of nested
inline markup: there are substitution references which serve for
deduplication, but some occurrences of the strings are emphasized while
other are not -- this is where I need nesting.

Could you please give me a gauge of

1. How difficult would it be to port the patch in
https://sourceforge.net/p/docutils/feature-requests/22/ to the current
version?
2. What happened to that and the nesting branch?
3. If both above are useless / too hard, how difficult would it be to
implement a "one level nesting" feature and whether you would be interested
in including it, even though it falls short of the target described in the
FAQ?

Thanks a lot,

Martin Koutecky