As per what I was emailed, copy paste:
"lead time is going to be mid to late april for next shipment."
That being said, they've been historically late fulfilling new products so perhaps it's safer to assume May, but either way you said there's no ETA for more which is not accurate. New orders...
There's 5 in stock now, and next batch is mid-end of April so not sure where you got that info. It's going to be a regular item that can be order like the rest of the Supra suite