cool project
... going to follow this with high interest
imho it screams for a late FJR 1300 engine shaft-feeding direct into a flipped Speedway Engineering baby IRS QC (FJR output rotates the opposite way then reg car engine)
the flipped QC would fix that problem , plus lower the cv flanges and allow you to fine tune final gear ratio in minutes ...
I would look into aluminum "Legends" spindles up front
maybe Jag/LS aluminum spindles in the back
I have looked into using the (sexy double shear mount) LS spindles myself , but abandoned the idea for now
super lightweight ... and wheel bearing id is the same as BMW hubs (930CV flanges
)
together with the 930 cv flanges of the QC your open for any axle lenght you desire (its basic dune buggy stuff)
need to take a pic of my mockup ....
btw
aluminum Mazdaspeed 3 brake calipers (with integral parking brake!) are a direct bolt on to the LS spindle bosses
(using the iirc 295mm x 9 mm mazdaspeed 3 disc)