No, no I haven't. But like I said, over here each lamb woud need an anaesthetic. That alone makes it far more impractical than ringing, not to mention the extra cost.
I know of a study by British vet's who reckon (don't ask me how) the initial pain of ringing is similar to the shock pain of the gas.
And obviously due to climate, all those things you're mentioning (fly treatment, worming etc) we aren't doing those by 1-4 weeks, so we'd still need to gather them all up again anyway.
Agreed when I used to lamb outside we left tails & balls on. Now I'm lambing indoors in Janua