It's ending up matching my "why you shouldn't take pre-orders" comments in previous threads. There will almost always be delays that are beyond your control, and these delays will string together with alarming regularity, to cause a very wide miss on your target product ship dates.
And it never reflects well on your business, or with your customers that often feel they were "promised" the product by a date you missed by a wide margin, regardless of whether or not you actually made a solid commitment. For some people, any shipping estimate you give will be remembered as a promise, no matter how you word it. That's just unavoidable.
Stick to your founding principles. You made them for a reason.