I'm happy to make a scenario if you want, what kind of map/size do you want it to be? And exactly how balanced? I have a nice 14 player template here:
https://www.warlight.net/MultiPlayer?TemplateID=709881If you want something like that I can make a 19 player version no problem, or if you want something more open-play (a rounder map) I can do that too, I could make a perfectly balanced one using a circular map if you want to keep it sterile?
19 is a difficult number to put into a perfectly symetrical system because it's prime. Do you think maybe you could make it 18 or 20, or even 21/24? If you want something with more variety though it won't be a problem.
EDIT: I quickly threw together a 19 player Diplo on a square map so you can see what I mean by something more sterile:
https://www.warlight.net/MultiPlayer?TemplateID=715370
Edited 9/14/2015 09:21:11