Decentralized product inventory (instead of simple orderbook) I am thinking of creating a decentralized market place with public bidding. AS far as I have researched all cryptocurrencies and such only offer public ledgers with simple orderbooks. The only data about the item you are exchanging is value like BTC->USD or USD->BTC. 

I was hoping to have a decentralized public market for more complex products which have many properties (let's call them CPU, memory, bandwidth, storage and lease time). In this case, you would not bid against a single value (price), but define the acceptable parameter ranger for your bid e.g. 30x units with > 512 MB memory, 1 MBit/s bandwith at the price of 1 USD/unit. 

Then the ledger would go through the offers and match ones available on the market. Then trade parties would exchange private keys, so that the buyer would get the access to the item. I have no idea yet how, but probably the buyer would have an encryption key in the bid and if the bid goes through then the seller would encrypt a reply to the buyer using this key (the buyer can only decrypt).

As I am still in early phases of my research, I was wondering is there any prior art in this kind of crypto markets? Preferably the ledger data and the orders are public in consensus or blockchain, so that the there is no single point of failure in the system.

Thus far I have researched 


NXT
Stellar 
Bitshares X 
OpenBazaar (this looks promising but orders and inventories are not decentralized ATM)
Ethereum (well this one is still much in baking)
I think Ethereum is ideal for this.  As you say, it's not ready for prime time yet. But I think it offers the most flexible toolkit for managing orders in a truly decentralized way. You can create and manage arbitrary database structures that are secured on the blockchain.

I wrote a toy digital artwork market using Ethereum -

http://robmyers.org/2014/07/24/ethereum-art-market/