feature request #'numbers-with-letters

I have found numbers-with-letters

1. Can the numbers be omitted (incrementing letters)?

2. Can the letters be made capitals (maybe even different other 
character properties)?

Both of these variations are common in stage musicals.

TIA for considering this or showing me what properties can be changed to 
accomplish this.

Kieran or someone has giving me code to do this one bar at time but it 
would be great to have this automated.

Paul