can anybody tell me, when IDNs will finally go live now, with the final prefix and everything? What are the reasons for the latest delays (at Verisign)?
They are live already. It is up to each registry to allow registration, employing additional per-TLD-restrictions, as the registry sees fit. Verisign manages just com/net/org, and there are much more ccTLDs which proceed at their own pace (even though, to my knowledge, .nu is the only one that has IDNA operational today).