Thank you very much for building the example code kactech. Stuff like this is really helpful.

Perhaps I could get advice on how to experiment with scripting?
I have been using bitcoind and pybitcointools. I have been having trouble getting the transactions to Eligius, which is the only mining pool that accepts custom transactions?

Since broadcasting custom transactions is such a pain, maybe we can come up with a way to do all the custom transactions off-chain?
And then we broadcast the final standard transaction normally?

Once a transaction has been signed, it is easy for either of them to verify that the transaction is valid.
Instead of broadcasting it, they can make an standard transaction that does the same thing, and broadcast that instead.

Only in the case where one person disappears do you have to broadcast the custom transaction?

I am currently trying to write code to implement cross-chain transactions, as well as trustless distributed gambling. I use bitmessage so that users can talk to one another. bitmessage is a proof-of-work based communication system where you can't even tell which addresses are talking to each other.

The code is a big mess right now. https://github.com/zack-bitcoin/python-bitcoin-library