Attach one animated mesh to another

Ok I have a situation where I need to replace parts in a mesh, think like a robot. Now there are two ways of doing this and I'm waiting for my modeller to get back to me on this, but these would be to either:

a)Have a skeleton that is animated and then attach meshes to the bones.

or

b)Each part/limb is its own animated mesh and I would need to attach/swap out the parts by joining the bones together and have them all run their animation independently.

Now 'a' seems simpler but 'b' has greater customisation potential.

How would I do either?

Also a little off topic but how the hell do I find a bone in a mesh by name? SkinnedMeshRenderer.Transform.Find("boneName") doesn't seem to be doing it.

Thanks in advance for any help.