Willing to debug bug #3542 (23.0.94; File access via UNC path slow again under Windows)

I understand that the release of 23.1 is not far away and I am a bit
worried that this bug won't be solved before that. Is there anything I
can do to help? I use a lot of UNC file names / paths in my work and
the current slowness is very annoying (both opening files and listing
them in Dired). As this was a problem in the past too it isn't
unreasonable to believe that the bug has reappeared by mistake when
fixing some other thing (could it be related to TRAMP?).

I am willing to go bug hunting as long as it's in elisp-land and would
like to get some hints on where to start digging.

For details see:
http://emacsbugs.donarmstrong.com/cgi-bin/bugreport.cgi?bug=3542

Thanks!

/Mathias