Replicators were good for producing a working phaser in DS9 "Civil Defense" and a working slugthrower plus a miniature transporter in "Field of Fire". Replicators were supposedly used as the basis of the exocomps, too, allowing them to replicate themselves to new shapes and functions.
There may be tradeoffs between size and complexity, but it sounds unlikely that complexity alone would prevent replication of a device. OTOH, size alone could be an obstacle, but we've never been led to believe that replicators would be particularly energy-intensive devices.
Except perhaps in VOY, where keeping replicator use to a minimum supposedly created energy reserves worth noting during the first season. But this was never explicated as the reason for the replicator rations. It's just as possible that the rations were there because so many replicators were broken; later on, they were used as a disciplinary technique even though the ship was back to full operational capacity. And simultaneously with the replicator use rationing, the use of holodecks was permitted without known limitations. OTOH, shutting down life support on a single deck was said to create useful savings, so that might be the yardstick by which to measure replicator power use, too.
Size could also be a limitation if replicators lose cohesion when creating large objects, or if replicator arrays are expensive to build and have to be the size of the target in order to work properly.
And as said, even if single-piece replication were possible, the ships might benefit from consisting of smaller pieces; that would allow for maintenance and repairs also at facilities that lacked starship-sized replicators.
Timo Saloniemi
