Did you PB Blast the bolt first? Also some heat to the bolt will help, propane torch, but not too much. I would keep using the method you are, if you can put that much force on it without moving anything, you'll get it.

I've had to stand on bars to break em free before, nice when it finally pops free!

Just remember to tighten it back up- I must not have the last time I did mine and the key got loose causing the pulley to wobble alittle and move on the crank. Not a good sound when the key pops out and jams into whatever it was while driving (I didn't know what it was until I had the pulley off). After a few months of driving around like this, the pulley was pretty stripped and moved about a half inch away from the key way. Thank God for parts cars!