Will do. (I'll probably wrap libixp.)
What do you think? In the mean time we can build some prototypes on different platforms.
The real reason why we don't know how and if this interaction model would work in practice - is the obvious absence of implementations.
A Lua client library for libixp should be pretty straightforward, looking at the source for ixpc. I might have that together this afternoon (particularly if my fiancee continues napping ;) ).
As for a server library, I'm still thinking about it, but passing an init function a table with callbacks for the various messages would be pretty straightforward - similar to LuaExpat's design (http://www.keplerproject.org/luaexpat/manual.html).
I'm silentbicycle on twitter, FWIW.