The ATXMEGA64A1-AU is now in stock at Farnell. I'm ordering a couple.
Leon Heller G1HSM
Your post prompted me to check Mouser and Digikey, and they both report having stock of 64k and 128k parts. Don't know if that is a new situation or old news.
They have had them for a long time. I'm in the UK and get free shipping from Farnell.
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