Basically the idea for a tool that I have is that the tool will allow the user to select some notes and then pull up the tool, which will show the current number of lines, then the user will change the current number of lines to the desired number and click on Change or Render or whatever, moving the notes to their correct lines with correct delay values. I’m sure this isn’t awfully hard to implement as it’s theoretically possible for someone to calculate this on their own.
I think this would be useful for those times when you nonrealtime sequence something which has a good groove but it is supposed to be two measures in your song instead of whatever length it is.
Maybe the user could also specify a change of LPB and when evaluating this would make the calculated delay values more accurate when increasing LPB.
Optionally the tool could also calculate the BPM required for playback at the same speed.
Assuming this works with the latest version I think it should do what you want. Well not from your initial title and description but from this comment:
Jam long and record you nice, groovy piece. Change the length of the pattern so that it loops sounding decent. Resize to desired length using tool. Obviously recording with a fast BPM and/or high LPB will aid in accuracy of length for looping.