I would immediately support any plain multisig scheme or sane long-address multisig TX proposal as possible first-stage on our way to P2SH to allow people play with it and get more time for preparing P2SH deployment.
+1.
I'd be much more in favor of using earlier multisig efforts to classify as IsStandard and creating OP_HASH multisig transactions:
https://gist.github.com/39158239e36f6af69d6f or
https://gist.github.com/dba89537d352d591eb36Developing such a large change as P2SH should be reached by consensus after sufficient discussion. Many didn't even hear about P2SH proposals until very recently. Something like P2SH may eventually be necessary for large transactions, I do see a lot of potential value in it (and think the developers put in a lot of good work coding & testing, which is highly commendable), but it is an endeavor that must be developed with sufficient deliberation and consensus. In the meantime, we should begin accepting multisig transactions as soon as possible, with a minimum of code change/risk for miners and users until P2SH has been fully explored. I'd be much more comfortable if there were not been any bugs discovered in P2SH code in the past weeks (let alone months), unfortunately there have been substantial non-trivial bugs in the P2SH code that had to be fixed.
I've switched my hashing power to deepbit.