As far as I know, no viewer implements this. One of the reasons is that to be able to export an object held in the contents of the object you want to export, the contained object must first be rezzed in-world... and this recursively (since the contained object may also contain other objects).
Because the link order is irrelevant and it does not matter... If you got scripts that rely on such an order, then they would stop functioning properly as soon as the object is modified (prims added or removed, unlinked and relinked...). You should instead use the primitives name or description to identify their use from a script.