This is most likely a single entity, and it has spent 10 million dollars just in November
What do you mean? Isn't this just SecondMarket buying?
It is assumed that SMBIT only buys BTC when some client buys their shares (10 shares = 1 BTC). If that is true, there seems to be a client who buys 2.5 million dollars worth of shares each week. But we do not know, really.
I don't really understand why we're assuming that it's a single client. Secondmarket just updates the aggregate figures every week or so, as far as I can see; how are we reading anything about number of clients purchasing into that?