Right. Alibaba and Taobao are perhaps the biggest competitors to Amazon's physical goods fulfilment lines. They still have problems getting meaningfully out of China, though.
It's a fascinating area, and there's still huge room in specialist verticals, though. Perhaps five years ago, I interviewed at a London-based company doing over a billion dollars a year in trade just in the global shipping parts supply area. Holistically, SilkRoad is another example of a vertical-specific offering, albeit unconventional. Earlier this week HN featured a job from a startup apparently focused solely on inbound US customs-clearance for importers.
There's clearly huge money in this area, and lots of challenges.
Cross closer to the manufacturing side, and people have been slowly hyping up something called JIT or just in time manufacturing... the idea of highly dynamic sourcing from a highly available network of partners. Reputation systems and legal considerations obviously weigh-in big here, and the promise has yet to be realized. The 3D printing world and its resulting prototyping machinery has also been accelerating in this area.
It seems to me that what is truly needed here is not a new centralized platform (oh, so dotcom-era!) but a generalized, extensible language for describing RFQs and quotations with the capacity to add detailed information regarding logistics (shipping, warehousing, customs clearance, legals), financial and physical settlement routes, and reputations (not just happily settled n previous transactions, but definitely supplied n units/period from prior fulfilments).
I believe that every wholesale business of non-trivial size will some day have open source platforms providing this kind of business intelligence, risk management and operational support (sort of like SAP on steroids), and that global financial, regulatory and supply-chain systems will become more open and decentralized in tandem with these changes.
I have a no-time-to-progress-of-late, but braindump-level-documented approach to this problem space over at http://ifex-project.org/ which grew from the disparate operational requirements of dealing with cryptographic and conventional currencies/settlement routes at http://kraken.com/