What are you talking about Turtle. All custom scenario games are not practice. And all custom scenario games are not rigged. I have two custom scenarios on one of my maps that are supposed to be pretty balanced (they were modeled after an actual board game). People have WWII scenarios. They are not rigged...
4th Succession war - play as teams (5 players) or 1v1: http://warlight.net/MultiPlayer?TemplateID=370891
1st Succession war - play as 5 person FFA:http://warlight.net/MultiPlayer?TemplateID=370893
Maybe you should try my scenarios some time. They are pretty fun. Not the same strategic value as a ladder game, but they should be balanced none the less.