Additional rendering features which would be very useful:
Selectable patterns to render.
Maybe something more intuitive than a text box but something to the effect of: [00,02,0A,0C-1A], perhaps even random ordering like [0A,02,1A-10]
default the box to [ALL] (first to last pattern in logical order). This would be very helpful in rendering loops and or parts of a song.
Repeat during render.
This feature is already partially implemented with the Repeat Pos. in the main panel. If this option could be presented on the Render menu as:
Repeat  and allow the user to repeat the song to the “Repeat Pos.” as many or as few (default 0) during the render.
I am a registered Renoise user and would be very pleased to see these features implemented.