I'd favour a small lift that can be operated by the dwarf that hauled the item(s) to the lift. That way you're guaranteed to have an operator.
The real quandary is how to fit the task "lift item" in the AI. After all, why would a dwarf use the lift to send the item rather than go there himself? Why would he need to send it to the top of the lift, anyway? Therefore I think we should introduce the concept of item destinations.
- Burrows would be item destinations.
- The most basic way to transport them would be the new stockpile type: mail, package, transport, inter-burrow, whatever.
- When would an item get a destination? Manual designation; as a workshop option (all products made in that workshop will get a specific burrow as destination); general orders (eg. send all plump helmets to the kitchen burrow; or, alternatively as a permanent rule: whenever a plump helmet exists, it gets the destination kitchen burrow).
- The effect: an object with a destination that doesn't match its burrow, will only be transported, not used. When its destination matches the burrow its in, it functions normally.
This would allow the player to manage which items go where, and give the dwarves a reason to use a lift. (Because the destination would be recognized by the burrow it was in.)