I am running a TeX distribution with only one binary. And with bibliography and index: these could be done with the Lua part of LuaTeX. True about the others.
Indeed, Norman Ramsey essentially reimplemented Bibtex in Lua: look at bibtex.lua.in in his Nbibtex; tarball avilable from http://www.cs.tufts.edu/~nr/nbibtex/
