It is what it is. I ordered mine back in August and got it in October and I'm in the US! Essentially, they are always in stock, they just build it when you order it.
It really makes more sense for AmigaKit to do it this way as this is a specialty item. They don't know what the demand is for these systems. So, instead of having a stockpile of these sitting on a shelf that may not sell, it really does make sense for them to be Build to Order.
Don't worry about the length of time it take to get it. I promise that the A1200NG that you receive will be a great machine and you will enjoy it. I'm typing this message on my A1200NG! It's a great system, it just takes a bit of time to get. AmigaKit will deliver exactly what you want and not let you down.