I have a box of 8 new ones, plus about 50 or so working ones from display board pulls.
They are not expensive and can still be bought in quantities of 1 and upwards from Noritake. They are not going to be EOL'd for at least 3 years. Stock will be available from that point only until exhaustion. However, apparently, they will be producing an electrically and outline compatible replacement beforehand.
The bottom line is, you should not be worried about supplies of the VFD. If there is anything to worry about, it's the handle, which is now starting to go into short supply with no source of replacement.
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One of the few remaining Mk1 owners...
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