No change here, still 'Not yet shipped. Ships: Delivers by May 28th' for my 64GB wifi version. Maybe the 16GBs are getting priority due to volume.
Anyway, prepared for shipment means it's left the production line and is packaged with your label on the box waiting to head to the airport in Guandong or wherever it is they make them.
Personally, I think some of the delay is because there aren't enough planes. 600,000 worldwide preorders have to go out next week on top of the 800,000 a week heading to the US. Assume you can fit 20,000 per plane, that's a minimum of seventy 747s or 707s which have to land, load, fuel and take off again every 50 minutes in 5 days - just for one product, let alone for all the other millions of products they export every week. Bigger than the Berlin airlift. I'd hazard to guess that the rice-paddy airfield in Guandong is easily bigger and busier than Denver or La Guardia or even Heathrow, yet with virtually zero passenger traffic..
Edit. Or maybe it's only 200,000 a week to the US. So that's okay. Plenty of planes then. 🙂