Comment Box.Net (Score 1) 222
Box.Net (they have 2 million users) has everything that you listed above, except desktop clients, which they claim are under development.
Google vs. eBay/PayPal 197
That's Unpossible! writes "Google has today made a small announcement on their blog which could shake up the landscape of buying things online : they are going to start allowing certain parties to sell items through Google Base, which people can buy using credit cards linked to their Google Account. According to another blog post, Google already accepts payments in this fashion for Google Video, Google Earth, Google Store, etc. How long until Google Base is directly competing with eBay? The framework is now in place."
