I believe everyone is moving towards using the bitcoin-qt system for signing, but I'm not sure. I'm signing with bitcoin-qt, let me know if that is insufficient. I don't have a PGP key yet, and this signature is easily associatable with the coins in the account it is coming from.
Contract signed from address: 12mwAvJywtQF5rJXHzdBQd4yq8EVD7NZqX
Signature:
HyhgIo5QfmPpuQw2iPAakBhp0sCP3BnnBjXiojs+rsaCcs4QGoo74xDUOthtn3wlKTmKDA7qYhZUR9Qhi3K/Glc=
(signed with bitcoin-qt 0.7.2-beta)
Once John has signed, I'll initiate the transfer.
John basically did in post #177 by confirming he is controlling the updated escrow address and signing the contract.
I contacted John and Graet once again after the contract update for the new address and expect them to confirm soon.