Very old thread for sure,, but an interesting topic for those who like to re-arrange midi files or there own creations. I often have had to do this with a client sitting patiently waiting for me to add another verse or chorus. The number part never bothered me as I put markers at each part, but then the fact that the markers don't follow the copy paste does bother me.
I always leave a blank measure before the count in. The count in will be 1 bar if no lead in and 2 bars if there is a lead in.
The coloured blocks are cool. That would be nice but I can see it will never happen.
My guess is very few people would benefit from a negative measure count, so they have never looked into this.