European-style butter ganaches have longer shelf life . . . worth a try?
Sounds like my type of operation........
You gotta go back and look at stuff 100 years old when there was no refrigeration
Nougat based (including croquant)
Butter ganaches can be quite shelf stable if you remove the 18% or so water in the butter....
Now for instance, honey is a partial inverted sugar
Dried fruits last for years
Pate de fruits are very shelf stable
Nuts and nut pastes/marzipans are good for 6 mths
Am I giving you enough information without "giving away" my farm?
Nut pastes (gianduja, marzipan) are good but you have to watch out for fat migration which will soften your shells over time.
Butter based ganaches are good, for even less water content you might try using clarified butter (you can buy it off the shelf from many restaurant suppliers).
The gelee/pate de fruit idea is very good. Combine it with a praliné/chocolate/feuilletine layer and you have a 6-month shelf-stable product with a great flavor/crunch combination.
Cream fondent based, citric acid to cut the sweetness.