I GOT IT!!!
I went to the guitar shop ready to get all hot and bothered with my "I am taking it today NO MATTER WHAT" attitude, but when the guy greeted me in the shop, I knew it would not be necessary - either it was finished, or he wouldn't give me any trouble about it.
Well, it was finished. I was led into the workshop (truly guitar-geek paradise) and met the luthier who did the work. VERY nice guy. The 51 was ready, but the didn't call be because he was still working on my other order (a Tele pickguard) and he was going to call when both were done.
The 51 has turned out very well. The action is ridiculously, stupidly low (maybe too low) but there is not any fret buzz at all. The neck I bought has been installed with no hiccups.
Now...
I recently bought a pickguard for it (the tiger pearl one) from GuitarFetish, and well, it didn't fit. Not even close. Only 2 of the 11 screwholes matched up, it was unever to the humbucker ring, and would not fit around the control plate without sending the whole thing off-kilter. The luthier and I spend half an hour umming and ahhing over it before deciding it wasn't going to happen. So at this stage the guitar still has the original pickguard; the mother-of-toilet-seat white that someone cut into a strat shape and sprayed black. I can live with it for now.
The other issue was the coil tap, which was not working. The luthier said that when he pulled it apart, he noticed that it was a (I think he said) 4 conductor instead of 2 conductor (or maybe the other way around), but either way it was impossible to tap. This perhaps confirms something I was always wondering about: was the bridge humbucker the original? I guess not. Another thing about the humbucker is that the strings don't line up with the poles, to the point where high E does not hover over the pole at all. Odd, because the bridge is well set, the nut seems to be ok, and the neck is on straight...
All in all, it is now a good, well set-up guitar. not perfect - not even close - but it sounds great and is really something different. And I was charged only AUD$101.75. I had budgeted AUD$180. The luthier said he installed the neck for free. Lucky me, because this is where the bulk of the time would have been dedicated.
Also, when I was told the guitar was ready, I was in such a good mood that I didn't even think to ask why the heck it took so long, although at one point in our conversation he did hint that he felt the shop was taking on more work than the 3 of them that work there can handle. I even noticed that he had an LED alarm clock in his stall, and over the clockface he had put a sticker on which was written "YOU'RE LATE!"
As my friend said "all's well that ends well".
As usual, sorry about the long post, but this has been quite a saga and I wanted to share it. Thank you to everyone for their advice and help and encouragement. I know I will be asking for more in the New Year when it comes time to replace that pickguard.