I recently had a thought while working on one of my songs… it would be cool if Renoise had a feature that allowed you to “lock” tracks so that all playback on that track would be rendered in memory before playback so that track would no longer take up many resources while playing… essentially renoise would be recording the entire length of the track to sample and then playing the sample instead of the track… but of course, ofsetting properly so you could play from anywhere in the song and stull hear the track. Cool Edit Pro (Adobe Audition) has done this for quite a while now, and it makes working with many tracks alot easier. It would also make playing tracks live alot easier, as you could lock all the tracks you don’t want to tweak realtime. Of course, one would also need the option of unlocking the track for further editing and knob tweaking 
you could always do it yourself by rendering that track individually and then triggering it @ the beginning…
It is currently a method to perform, but it consumes some time…
Render it to a sample first, adding a track and calling it “Locked_guitar_riff” etc. It works. But having it temporary rendered in the background, loaded to memory and then connected with relative offset-segments would be a nice addition. (Using ghosting technique would trigger the sample from the relative offset it would be from last starting position)