Next to the "choruses", add a feature where the user could specify the % the tempo should be increased by. When I am working on a new tune, the tune would be repeated and the tempo increased by the desired percentage for each loop/chorus.
I am doing this with other music software.
I believe what you want is already available in Band-in-a-Box. It's called the woodshed feature. The text below is from the BiaB Help file.
Woodshed Tempo (Change tempo every loop)
When practicing (or "woodshedding") a tune, it is useful for the tempo to speed up every time the section loops or the song restarts from the beginning.
Press the [Practice] toolbar button and select Woodshed (increasing) Tempo… from the pulldown menu.
This will open the Tempo Woodshedding dialog. For example, if you set the "Woodshed tempo" value to 5 in this dialog, the tempo will speed up by 5 each time the song (or a highlighted section) loops to the beginning.
The idea is that you start off with a slow tempo, playing the part perfectly, and keep this up as the song tempo increases.
When you press Stop, the tempo reverts to the original tempo.
There are four modes to the woodshed tempo field.
1. "Up only," which is getting faster each loop "forever," well until tempo = 500, which is BB's maximum tempo.
2. An " "up then down" mode that goes up by [a settable increment] up to a [settable maximum] and then starts going down by the increment back to the original where it restarts. For example, a song with a tempo of 140, if you set the tempo to increase by 5, to a maximum increase of 100, the song will go from 140,145,150 etc. to 240, then go to 235,230… back to 140 and cycle again.
3. An "Up then Reset" mode, that goes up in increments up to the settable maximum, then resets to the original and starts again. For example, a song with a tempo of 140, if you set the tempo to increase by 5, to a maximum increase of 100, the song will go from 140,145,150 etc. to 240, then go to 140 and start again.
4. An "Up and stay at Max" mode that goes up until the settable maximum and stays there.
Modes 2 and 3 are analogous to a "treadmill workout," with programmed changes in speed