BTCChina topped at 4879元, equal to $800.89, and is currently at 4750元, equal to $778.99.
Why so high? Is it like Mt.Gox, where withdrawals cannot be processed? Or is it because yuan is to difficult for arbitragers to obtain?
All of the above.
a) BTC China has monthly withdrawal limits which are relatively low
b) Bitcoin is "newish" in China and thus there is more localized buying then selling.
c) Yuan is essentially impossible for foreigners to obtain. To deposit or remove funds on BTC China requires access to a Chinese bank account.