> I would like to adapt LaTeX for LuaTeX, and I'm looking for some people 
> to help me. If you want to help please subscribe to [log in to unmask] 
> (http://lists.tug.org/luatex), the discussions will take place there. I 
> already started a discussion on it: 
> http://tug.org/pipermail/luatex/2009-February/000103.html.

Just joined (I didn't until now). In fact, inputenc and fontenc
pose two quite unrelated challenges - the former is necessary
for LuaLaTeX to work with encodings other than utf-8, while the
latter is more about taking advantage of the new features, but
note the LICR mechanism used in LaTeX works in LuaTeX, provided
the issue with font encondings is solved (and my little
lua-inputenc does that, mainly for testing purposes, but which
makes LuaLaTeX useable with old documents - I even could make
my experimental Mem package to work with it, to my surprise!).   

And as Arthur said:

>  fontenc would surely be a much bigger issue.

Indeed, it is. I've paused my work on a new font mechanism,
but my conclusions after the tentative lua code I wrote is this
task is far from trivial.