I think they already started going there, at least in the UK. All my latest orders were delivered by 'Amazon Logistics'.
It's quite attractive to us as a retailer as they take all the negative feedback, handle returns, etc etc. FBA makes us, as a retailer, look good and saves us money (no shipping costs), while protecting our reputation.
From a logistics point of view it simplifies things immensely (we just need to manage stocks in another warehouse).
Coding this should, however, be interesting :)