I had a similar problem with a very nice guy. He had an issue with saying "I'll send pics tomorrow" or "I anticipate the knife being done in two weeks." Month after month this went on. A month before I went to the blade show in 2013 (and about 4 months after his own quoted deadline) I told him that if he couldn't get the knife done then I was canceling the order so I could buy one at Blade. He sent me an email giving his personal guarantee that it'd be done. Well, Blade came and he said "one more week." I went to Blade, had a great time, missed out on several knives that I wanted, and went home. The following week, still nothing. No pictures, no specific info as to what needed to be done to complete the knife. As nice as the guy was, it was 5 months after his initial deadline and he broke his "personal" guarantee. I cancelled the order.
Had the guy never made promises he couldn't keep then it would be different. Seems disrespectful to me.
Anyway, I heard a maker say that he'll tell a potential client straight up that there will be no guaranteed completion date, and no ballpark guesses, either. He'll give a generalized time frame of how quickly things normally get done but with the strict caveat that things may not happen that way with this specific build. It may take two weeks, two months, or two years. If the client cannot handle that, he's free to find a different maker who may or may not live up to the client's expectations.
I think that's probably the right way to do it. Anything less is setting the client and/or knife maker up for disappointments at some point or another. If you're a knife maker in it for the long haul, the last thing you want is to be considered a flake, a liar, unreliable, or any other pejorative word. Might as well get the things under control that you can, like quality, and leave some room to breathe where you can, like timeframes.
One of the worst things to do is to over promise and under deliver in any capacity.