OK, now I am worried too. Since I also rated him, here's my story:

I had the following casascius coins that he wanted to buy and I wanted to sell: 5BTC, 25BTC and two 1BTC. He insisted that I should go first and we decided that I would send the 5BTC first to gain some trust. That went perfectly fine, I sent the coin and received the payment as soon as he received it. Then I insisted that he should pay me at least half the money upfront for the other coins, but he didn't want to. We traded a bunch of PM's and then I agreed to send him the coins first. According to USPS, he received them last friday, but he hadn't payed yet because he is waiting for 120BTC that he bought on coinbase. Yesterday morning he told me that the transfer from coinbase would clear during the day. Haven't heard from him since.