FT2 had this undocumented command Kxx which basically mixed noteoff and note delay:
C-4 01 0000
--- 01 0K03
by putting a K03 on a row, you produce a note off at the 3rd tick of this row.
this would be extremely useful in MIDI importing accuracy, and is also very useful in normal tracking
quite easy to implement, also, I think
you can do the same in renoise with
C-4 01 0000
OFF .. 0D03
I’ve used Dxx in every possible way, but never thought this.
ME DEFINATELY LAME
sorry…
moving to Tips&Tricks
Still:
C-4 01 0K03
or
C-4 01 0K04 0D01
A dedicated note-off command can be useful after all.
You can play more precise short notes.
A ‘must have’ for midi keyboard users.
D(>0) on pan-column + note-off makes no difference with longer notes but
the instant note-off trick is incredible 
on a side note, I must say that I’m not lame, but just getting old:
I’ve already used this trick in old songs made with ReNoise but forgot it 