For the example of the machine frame, the simple solution is to have a crafting ingredient whose only recipe includes itself. Then when the player meets the threshold, you give them one of that item. They can then replicate it as many times as they need. With HQM you can even make the quest repeatable so they can get a new item if all their copies are destroyed.
Also, if you think about it, this is a very common thing in mods. Lots of items and blocks are gated behind some level of machine. IE, you need a induction furnace to get enderium. The "gate" can be practically anything. From access to the nether, to getting a nether star, etc.
But for a HQM reward, I would go with the recipe thing.