I think what you want is not Recess but a module exposing the Drupal framework in a similar way that Recess does.

I think version 2.0 of this module is what you want: http://drupal.org/project/rest_server If it's weird how to use it or if it's scary that it's unstable - please talk with the developer of it in it's issue queue - his a friendly person :)

Since Recess is a framework in itself you would end up running two frameworks if you just added it on top of Drupal.

If the two was to be combined it should ideally be by making it able to plugin in some of the Drupal frameworks back-end stuff, like the database layer etc, in to the Recess stuff - but that is also something that would probably have to wait until Recess has matured in to a state where it has a pretty stable/solid base to do such work on. It would not be nice to do a Drupal-Recess bridge and either having it being broken every time Recess evolves or having it stifle the development of Recess.

Xavier, Have not tried to run from within Drupal. The routes are abritrary, though, so if you get Recess running in the root directory you could set an application's prefix to be "recessmodule/"