As of today, the Szell box is making a strange reappearance as being available on "Back Order" on two sites -
https://www.importcds.com/george-szell-the-complete-album-collection/889854718527 Listed at 163.93 USD
and
https://www.deepdiscount.com/george-szell-the-complete-album-collection/889854718527 Listed at 178.56 USD however if you agree to join their mailing list they will send you a 10% off coupon.
A week ago, the Szell box was only listed at jpc.de, fnac.com, and grooves.land. And, as mentioned by others, is no longer available from any of the three.
It seems somewhat implausible that Sony would go through the considerable expense of re-printing this once again in such limited quantities that it would sell out even faster than the original release. This would appear to be yet another victim of supply chain issues and may eventually be as readily obtainable as both the Walter and Ormandy boxes.
I wouldn't lose hope - If you want it, place your order with importcds.com - Better track record with packaging than Deep Discount.
As mentioned, the Szell box had been missing in action for years on importcds only to suddenly make a reappearance in the catalog listing yesterday.