a.coffee

require 'b'
this_ is_ file_ a

b.coffee

this_ is_ from_ b_

bash.sh

$ coffee -p -r ./require.coffee a.coffee
(function() {
this_(is_(from_(b_)));  this_(is_(file_(a)));
})();

require.coffee

fs = require 'fs'
CoffeeScript.on 'success', (task) ->
  return unless task.output
  task.output = task.output.replace /[ \t]*require\(['"]([^'"]+).\);[\r\n]*/g, (line, file) ->
    CoffeeScript.compile fs.readFileSync(fs.realpathSync("./#{file}.coffee"), 'utf8'), noWrap: yes