Note: I am not the author of LuaRocks (https://news.ycombinator.com/user?id=hisham_hm is), just a user.

Regarding distribution, what OS are you talking about? LuaRocks is available in Homebrew for OS X and as a package in most Linux distributions. Windows build looks a bit more painful but I don't have experience with that OS.

Regarding per project trees, there is no such thing as what exists in Python with virtualenv, but you can certainly do this:

    $ mkdir my_project
    $ cd my_project
    $ mkdir rocks
    $ luarocks-5.2 --tree="./rocks" install haricot

This will install the latest version of Haricot and all its dependencies (in this case LuaSocket) in the local tree regardless of whether you have them system-wide. Note that you can change this behavior (http://luarocks.org/en/Dependencies) but the default dependency mode is "one".