Patrick,
There are a couple of ways I look at this situation.
Mick apparently keeps a book on orders and builds them in the order they come in. The extended wait could be due to Mick slowing down production to make sure there are no QC issues with any new units.
Another possibility is since Mick builds several different preamps and amps, the more expensive units (read: more profitable units) may get pulled out of line and built first. For our sake I hope not, but as a businessman, it would be very tempting to make the most money as fast as you could. And I am not sure there would be anything unethical about it as long as no promises were made to anyone about a specific delivery time. Mick has always been sufficiently vague about delivery time and I can't fault him for that. He is a one man band and delivery promises are often difficult to keep, especially when there is great demand for your services.
But for all of us who are waiting, I just hope the wait is worth it. If I receive a first-class preamp with first-class sound and no QC issues, the wait will be no big deal. And if I didn't have confidence that my expectations would be met....eventually.... then I wouldn't have ordered anything from Mick in the first place.
Aloha,
Warren