Wow. Thanks for all the positive energy, gents. 
I'm somewhat happy to inform you that the goalposts have shifted again, somewhat. This beastie is STILL going to remain Toyota...but with a bit of a twist. What it is going to eventually become is going to remain a surprise for a few days, while we get logistics sorted out.
The reasons for this change of plans are fairly simple and straightforward. Firstly, the FJ45 body I'd found. I discovered this, in the Astabal (Stable) second hand market of Pindi. The body was rusted, dinged, battered and in a bad state, but it did seem to be retrievable. So...I went there and met the owner. Instead of him asking 60K, he decided to up his demand to 80K...non-negotiable. Probably looking to make a quick extra buck, on the side. After a polite cup of tea with him, we decided to give up on this idea, altogether. 
Next, a visit to City Sadar Road, turned up nothing new. We found loads of FJ40s, but all of them were the open-topped variety...fresh from Army auctions. These didn't really suit my concept of what I wanted to do with this vehicle...that is, a closed, short cabin...and a short pickup tub in the rear. So we went onwards. To Tarnol. What we found THERE, is what is going to stay a surprise, for now. 
The third factor was cost. I'm certainly not averse to spending money where it's due...but I'm not at ALL fond of needlessly spending money on projects that are irretrievable. The FJ45 body was indeed a possible resto project, but was just too expensive (and labour-intensive) to warrant serious consideration.
Lastly, and most importantly...creativity. As a hobbyist, I've been building cars for a very long time now. And the 'challenge' to take things one step further, is what keeps my interest alive in this wonderful sport. Building another FJ40 / FJ45 wouldn't really have been that much of a challenge, any longer. With most parts of the frame in order, the thought crossed my mind, that we were pretty much at liberty to try and 'push the envelope' a little further. And that is exactly what we're going to do, Allah be willing. 
Hopefully, by the end of the day...or latest by tomorrow, we should be getting an idea of what this project is finally going to turn out as. It's going to have some hot-rod elements, some off-road buggy elements, some vintage elements, and some plain old-fashioned BADA$$ elements. Rest assured, though...it's going to be something VERY naughty, indeed!