I funded my initial Bank Direct deposit with a check. I then set-up a link with my regular bank to do ACH transfers, which are free at my bank. With ACH, I can send funds to/from Bank Direct and my regular bank on a next business day basis. My regular bank holds funds for 3 business days. So all in, it takes about 4-5 business days from when I start a transfer to have cleared funds in my regular bank.
I haven't tested this with Bank Direct using large amounts but I see no reason it would not hold up.