you have done something great! I will have a look at the code within the next 10-12 days and get back to you with some feedback!
cheers.
Small update - I've added a few new features.
- Allow any m-of-n (not just m-of-3) transactions
- Support for partially signing transactions
- Support for adding signatures to raw transactions
With the above, ms-brainwallet should work well for doing things like escrow and without to share private keys or have all the private keys in one place.
Hope people find it useful!