Rendering Unicode diacritics

While doing Inupiaq and Aleut linguistics I've discovered that Tk, like
most of the software on my computer, can't properly render Unicode's
combining diacritics (the biggest disappointment being Inupiaq's
dotted, barred l (\u0142\u0323), where the dot is placed way too far to
the left--a real show-stopper). This is something I'd really like to
see fixed; as a first step, I'm hoping some of you can help me get a
feel for the scope of the problem and what it would take to solve it.
If anyone can answer the following questions, or suggest questions I
should have asked (preferably, complete with answers), I'd be quite
grateful.

What does Tk currently use to render Unicode text on Windows, OS X,
Linux and Unix?

Are there any specific plans to improve Tk's Unicode rendering?

What would it take to incorporate SIL's Graphite rendering engine
(http://scripts.sil.org/cms/scripts/page.php?site_id=nrsi&cat_id=RenderingGraphite)
into Tk on Windows?

Does anybody know of other possible solutions to this issue besides
Graphite?

Thanks,
Aric

P.S. I'm on Windows XP, running Active State Tcl/Tk 8.4.11 and 8.5a2
and with a pre-MS Office 2003 version of Uniscribe, in case that
matters.
Received on Thu Sep 29 14:39:01 2005