Implementation of contracts and nLockTime

[mjb]

Are there any real-world (or experimental) implementations of Bitcoin contracts that make use of the nLockTime field, as outlined in https://en.bitcoin.it/wiki/Contracts ?

As of four months ago, there did not seem to be any, although the discussion in this thread was very valuable: https://bitcointalk.org/index.php?topic=131443.0

And, finally, do I understand the following correctly:
Transactions with an nLockTime set (far) into the future might get dropped from the memory pool of all Bitcoin network nodes, which means that it is insufficient to rely solely on the Bitcoin network for persistence of locked transactions and you have to refresh the transaction from time to time from outside the Bitcoin network?
Can anyone speculate on what would be the average lifetime of a locked transaction under current circumstances in the network?


Cheers!

[gmaxwell]

There has been some experimentation with them— but not contract usage. Due to some attack usage we actually will not relay (or mempool) locked transactions at all right now.