Thanks for the suggestion, Ben.
Following the recent release of Improvements to Planned packaging and delayed racking release stock control (allow overselling if stock will be available in time), you could use a planned packaging in the future to handle this. This would, in effect, give you the feature you’re asking for, but with specific quantities of the future stock and per-product future dates.
Can you let me know if the planned packaging solution would work for you, and if not why? Thank you.