You can.... it is possible. 

I believe the chances of getting a PayPal chargeback/refund are directly correlated to the level of effort (and a bit of luck) put into the process.

First step is to dispute through the website.  That'll immediately be closed.

Then follow some of the steps outlined in this thread previously.  Persistence and a good attitude can go a long way toward PayPal giving you a refund.

You only think difficulty will be 50M at the end of August when BFL is shipping in mass, ASICMiner deploys and sells their second generation blades, and hundreds of thousands of Avalon chips flood the market?

Terrahash can you please confirm/deny this or consider revising your que based on payment.

If not, than I am in the market for a sub 500 orders of if someone has them available and they are looking to sell and will be canceling my current orders as soon as I find them.