Check out MoreWine and Shore Container
(BTW: with Shore, it is cheaper to place two orders of three cases each, then to just order 6 cases - 3 seems to be their sweet spot with shipping)
Edit: What am I saying? You should call your local winery contacts. They probably have bottles to sell you or would allow you to piggy back on their order.
That's where I'm getting them. $12.00 a case for commercial weight bottles.