Thank you, Suhaib. 
That's a really good photo for comparison's sake! Fortunately, one of the major problems which might be encountered would be having any wheels wells at all, which this little Phantom will NOT be having. The 40s are notoriously cramped in those areas...and ask me how I know this :).
Yesterday, I was doing a quick visual analysis of both of the frames. I have a feeling that since we're virtually rebuilding the entire frame from scratch, we'll have a half-decent opportunity to ensure that all the control arms, shock towers, cross-girders and strut points are grafted on where WE want them, as opposed to where they originally are. By virtue of this, we'll get the wheels to sit where desired, the engine to be mounted where we want it, and the cross-girders to fit where it's most convenient.
Secondly, having chimtey rather than leaf spring stacks front and rear, should be helpful in allowing a suspension drop...and let us go about lowering the frame, rather than just the body. Hopefully, the body channeling will allow us to create the visual impact of it being lowered further...as will the roof/body chop. Since the car isn't going to have any fenders, wheel-wells, engine bay side-walls, or a rear tub/bed...we should NOT have any sort of problem with regards to tire fit and/or chafing/rubbing. Nor should we have much of a problem with regards to lack of travel.
Lastly, I'm very seriously considering adjustable Ranchos (I think the 9000s) for the shocks. Again, theoretically, this should enable us to adjust the ride firmness as per our requirements. Although, I'd love to hear if someone has actually used these shocks, and whether or not they're suitable for raising/lowering ride height.
Overall, I think the beauty of such a build is that it allows the focus to squarely remain on the mechanical aspects, and is a triumph of function over form. Let's see how it actually turns out.
