First off if I remember correctly, which I may not, I don't think suppliers can respond here in this section of the forum so you probably won't get a reply from any of them.
Also, you have to look at it from their point of view. They may be working on order #xxxx and if they have it posted on their site then they may get people placing orders and seeing that their order number is too far past the currently posted order # for their liking and then turn around and cancel the order which causes more work for the vendor. Or many other ways that people don't think of that such a thing could turn into a hassle.
Also having an order number posted doesn't really do anything but give those watching it a false sense of knowing what is going on. A vendor may get 47 orders done one day because 40 of the orders had only 1 or 2 bottles on them but then the next day only get 6 orders done because they all had 10 bottles or more.
While some people may like the idea of it and be reasonable about it others would use it in a way that would cause more headaches for the vendors and slow all of our orders down.
edit: there was only one response when I started this reply and I see I may be wrong about the first part since Angus didn't mention it in his post.