- Is it possible to have MORE THAN ONE luatex cache directory?
I'm not sure if this really makes sense, but you may want to know that luatools looks up a number of environment variables consecutively to determine the location of the cache: first TEXMFCACHE, then HOME and other similar variables, then VARTEXMF and similar vars, etc. (see line 3768 of luatools.lua for the complete list). I guess this could do the trick: the installation could generate the formats and put them in $VARTEXMF, and each user could put his own files in $HOME and override the defaults if the wants to (provided TEXMFCACHE is not set); but I need to check if this indeed works (not sure).
- Is there an obvious objection to replace luatex binary with a script which contains the necessary TEXMFCNF settings
I don't think this would be any problem with the ConTeXt developers, but you need to account for the fact that LuaTeX may be used with other formats. That's what I told you in the other thread: all these settings are related to LuaTeX but they're really specific to ConTeXt, and if someone wants to use LaTeX over the LuaTeX engine he may not be happy that the settings are not exactly the same than for the other engines. Of course if you only set TEXMFCNF and nothing else this shouldn't make any difference. Arthur