[bret]

I've got a fair amount of experience with this style of build in our street rod market. The full chassis route is certainly a viable option for a high end build, especially if the existing frame or floorpan is already shot. Roadster shop, Ironworks, and several others can accommodate nicely.
If it is reasonable shape then the stock frame can be worked with in an effecient manner.
For the frontend, few have more hands on experience with "unusual" cars [especially the 50's cars] than Fatmans. Not only do they do a specific front clip for this car, they can answer a multitude of your other questions about the build because they been under those cars personally all their lives.
On the rearend, a triangulated 4 link works well. While there is no "model specific" application, the components are highly adaptable and the installation is straightforward.
With this approach you still have the choice of air cor coilover. I personally like air for these cars because there is no compromise in performance AND they look bitchin on the ground!

Sounds like a cool project...good luck!