WPC projects are getting tough to find in general since most are moderately to very desirable. Expect to spend $1500-$3k for a game that flips. A donor game really doesn't make things a whole lot easier or cheaper, though. Maybe when a donor game could be had for $200, but with popularity where it is now, everybody wants project games.
Considering TAF's can be found for $4500-$5500, I would recommend buying one outright instead. It would be much cheaper and easier.
I did a partial spreadsheet work-up a year or two ago of what it would take to do a scratch build of AFM. The parts availability for that is a lot better for that game than TAF and the BOM is a lot smaller as well. And still it was not cheap, and there were still dozens of critical parts that were unobtainable. It is simply not practical no matter how fun you might think it might be.
If you really want to scratch build a game, you would probably be better off designing and building your own custom game.
Quoted from whthrs166:Reading this makes me wonder if this kind of thing will be more likely to happen in the future. With game prices going up and availability of the classics constantly reducing at some point in the future would the cost effectiveness become a reality?
Not really. It's still way too much work, way too expensive, and too many parts are NLA to be able to build from scratch.
I doubt someone would offer a kit to build a game either. Too many logistics issues.
CGC has the right idea about remaking popular classic games with a high market price in the collector's market. However, they seem to be sticking to non-licensed titles for now, so TAF probably wouldn't be on their remake list anytime soon. I imagine it's on someone's wishlist, though.