Hi Chip
I think you probably know the answer - it's all down to how many kits would sell.
Koster do an excellent vacuform model and FM sell a short-run injected kit which "owes a lot to it" shall we say..., but as regards any of the major manufacturers bringing out a Harpoon / Ventura in 1/48 scale? Maybe Trumpeter? Who knows... I'd certainly love to see one.
All the best
Rowan