Dear Sir,
I am a mechanical engineer with experience in product design. I have made many folded metal sheet, thermoplastic and mechanized parts for short series products.
Proficient in 3D CAD I may take your project to the product.
The search space of possible solutions has to be narrowed because it is too wide now.
To start with I would ask the following questions:
1 - describe the intended use of the conveyor. I may understand your caution, but knowing it will guide the project to acceptable known solutions.
2 - describe the intended quantity : One, less than ten, some hundreds?
3 - describe your manufacturing capabilities.
4 - talking about sturdiness, indicate the size, weight and speed of the products to be transported.
5 - I am assuming an electric drive. Correct me if you prefer compressed air or other.
Sometimes to have reduced specs seem to help the designer, but in fact the restrictions are the guide for the design.
Best regards