I can provide you with historical JSON trade data from the Coinflow site.  It has several months worth of bitfunder, havelock, and MPEX data pulled from IRC bot logs, since these sites don't have APIs with historical data.

Just replace '/chart/' in the URL of any page with '/json/' for the JSON data.

For example, any bitfunder JSON is at /json/BF/, for example, http://coinflow.co/json/BF/TAT.ASICMINER

I might work on creating a more complete export if there's demand for it...  I record whether it's a bid or ask, but that's not in the JSON currently.