Since the game is about "making parts", to "make structures"... Why don't you use that to "all of our advantage"?
For instance, the dinosaur. It could be three individual parts. (That would also resolve the LOD issue.) Having the head, the body and the tail as three parts, built into a "blueprint". You could make a short neck, a medium neck, a bent neck, a fat neck, a thin neck... and/or tail... matching the body. Then, for more flavor, various bodies... One with a leg-up on a rock or "nothing". One rearing-up. One laying down, sleeping. One bent to the left and another bent to the right.
You end-up with more than 100,000 potential shapes, from about a dozen "individual parts".
This is where creativity comes to light. Large trees, buildings, cars, animals, etc... all gain from this process.
Not sure if it is possible, but if the "bones" can be "scaled" in the game, after loading... You can simply add ONE bone to the whole object and "scale it down", before exporting, then when in the game, have it scripted to "scale the bone up", on XYZ axis. (I wish a few items used that feature, like trees, for size variations.)