I guess it’s just a matter of time until this will be possible. Some of us are developing a windows frontend and some php scripts (which are multiplatform), which can perform various task with the xml based Renoise files. You can check the current progress here:
In the following thread Marc Shake has found a nice php class for converting an intermediate xml format into midi. I’ve read in some other thread, that he is working on a conversion script allowing you to save a xrns as midi file. 