This has been reviewed by merchants, miners and exchanges for a couple of weeks, and has been implemented and tested as part of the Bitcoin Classic and Bitcoin XT implementations.

Constructive feedback welcome; argument about whether or not it is a good idea to roll out a hard fork now will be unproductive, so I vote we don't go there.

Draft BIP:
  https://github.com/gavinandresen/bips/blob/bump2mb/bip-bump2mb.mediawiki

Summary:  
  Increase block size limit to 2,000,000 bytes.
  After 75% hashpower support then 28-day grace period.
  With accurate sigop counting, but existing sigop limit (20,000)
  And a new, high limit on signature hashing

Blog post walking through the code:
  http://gavinandresen.ninja/a-guided-tour-of-the-2mb-fork

Blog post on a couple of the constants chosen:
  http://gavinandresen.ninja/seventyfive-twentyeight

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Gavin Andresen