Brisbane
Good timing, I am going through EXACTLY the same thing! I have accumulated many TAF parts over the years (mostly used), and have just started putting it all together.
I agree with comments above.
The problem is not the obvious big ticket items (decals, pf etc), its actually all the small bits you dont think about. At the end of the day anything is possible if you are patient.
A couple of things I have noticed about parts in general are the following;
- Under p/f light boards are bloody hard to find! I think this is due to them being theme specific, and not really a part that broke down, so no aftermarket options. I have all the light boards bar the mansion one, so will need to use screwed lampholders for this area.
- Knocker assemblies are unobtainium for some reason (doesn't impact gameplay though)
- New theme specific parts are expensive.
I have noticed that its easy enough to find new metal scoops, the swamp metal work, ramp etc, but now pinball has kind of gone crazy these parts are not cheap. I doubt you would be able to buy all the parts to build a TAF new for less then what you could buy one in fair to good condition.
Quick sums in ($AUS 
);
P/F $1000
DMD $300
Translight $150
Decals $250
Legs $100
Board set $1500
P/F parts new $2000+ ($3000+ if you need all the metal work as well)
Cabinet $500? (I make my own so only pay for timber and paint, so probably more like $1000 really)
Cabinet hardware (lockdown bar, coin door, wiring harness etc) $500
All metal guides and wire forms will need to be made from scratch
New plastics set $200
Already at $8000 without even getting into the finer details!
Then your looking at the wiring harnesses, which can not be purchased so would need to be made from scratch. Massive job!
Expect to spend 2-300 hours putting all this together also..
I would not have bothered attempting this if I hadn't picked up used parts over the last 6-7 years.
... 
Rancho Cucamonga, CA
