I agree that the math is easier when bitcoin prices are going up, but I believe the protocol's control of hyperbitcoin prices and effective leverage also prevents default as described above. A more extreme situation, with panic-selling of both bitcoin and bitcoin-backed pegged-value tokens would require a more extreme response, for which I outline a couple possibilities in the first post of the sister thread:
http://forum.bitcoin.org/index.php?topic=31645.0I've read this thread and I still think that your system has the risk of default (and the subsequent collapse).
Since you can't print bitcoins (not even for a while), you can default.
I don't know what is wrong with the derivatives with bitcoin escrows. You still get what you want, oil-coins.
You are correct that all currencies and commodities tracked would need a real-life counter-party (the escrow fund itself cannot be taking positions that have a net long or short position against oil/gold/Euros/etc). That is the intended function of GoldCoins vs AntiGoldCoins, etc.
If I've understood vector76 properly, you would have an oil-coin versus a derivative short oil and long bitcoin.
The problem I didn't get about fungibility is that any of the parties could redeem the contract at any time.
That problem could be reduced if the system can look for contracts enders on both sides of the bet.
Remember that both sides of the derivative are always solvent (or the contract is automatically redeemed).
I also came to the conclusion that you cannot use bitcoins for the escrow, because maybe you need to transfer bitcoins of it from a user to the other and you don't own the private keys.
You need derivativeCoin.