Anyone who, like me, had coins stored in Coinbase's multisig vault during the Bcash fork, still has not gotten support from Coinbase to retrieve his forked coins. I just got an email from Coinbase telling me they know I have coins there, and that they're working on adding support, with no commitment to a timeline.
So, I made a fork of Coinbase's multisig-tool which I've successfully used to extract my coins. You can find my fork at
https://github.com/danra/multisig-tool/tree/bcash_extract .
You're welcome to use it if you're in the same situation, but of course do so at your own risk. You can read more details in my commit message at
https://github.com/danra/multisig-tool/commit/ecefc9086002ca9a065a6beba3add564271f6c0f .
Something which is still missing and shouldn't be too hard to add, given the right API (which I haven't been able to find myself) is automatic detection of unspent Bcash outputs; currently, you have to enter all the details of your unspent output manually, which is a hassle and error-prone. If anyone is willing to add this over my fork and complete the tool it would be awesome.
Please note my motivation for doing this was my guess that by the time Coinbase add support for extracting Bcash coins from their multisig vaults, the coins might not be worth much. If you think differently and have forked coins stuck in a Coinbase multisig vault, it would probably be more prudent to wait for formal support from Coinbase.
Thanks,
Dan
