1. Wait until a core dev signs a release of bitcoin core in which the limit is double it's current level.
2. Use the new release to mine, but use a soft limit on the blocksize to produce only blocks that are valid according to the old software.
3. Wait until May 5th, 2016.
4. Remove the soft limit on blocksize.
   
5. Create a block that breaks the old limit and is valid according to the new signed release.
6. Wait for the new large block to be orphaned.

Hopefully, the reward will be greater than 25 bitcoins and therefore cover the transaction fees.  Of course, if they wait until after the halving in step 3, then they will get twice the (new, 12.5 btc) reward if they can arrange for the orphaning of their own block.

Any core dev could do this but I guess it would be playing with fire.  So maybe Satoshi will do it.  He played with fire (right?) and look how that worked out.  Come on, someone, be a hero.  Mike and Gavin tried, but I think they went a little overboard.

Another way to do this is to identify the position in each binary where the hard limit is stored, and write a little script that will (check the date first, and then) alter the data at that position so that currently running bitcoin software can be hot-patched on May 5th without the help of any core devs (if that would work).  Obviously, the little script should be signed by a competent programmer whom the user trusts, a slightly less stringent requirement than being an actual core dev.

notplato