If they had significant reserves at Mt. Gox, then they would make a withdrawal of Bitcoins from there, and be able to fund all reserves at all other places with those Bitcoins. They would then instantly turn on the Cash to BTC function since they would have Bitcoins to send. Since they haven't done any of this, it's pretty clear that they do not have significant reserves there or anywhere else. This is further evidenced by the fact that you, along with all the people that have posted here and many others that don't even know about this thread, still have outstanding, unresolved orders.
The proof is in the pudding - this could all be resolved within a day if they actually had funds, in any form, to back up any of the transactions. Again, the fact that this thread exists and people continue to send them money, followed by shock that their order hasn't arrived, is mind boggling to me. I suspect even the Bitinstant people themselves are stunned that money keeps coming in.