In terms of your rack location problem there MAY be a solution in the design used in the Lotus 63 FWD GP car of 1970/71.
Because of the front diff. unit there wa no space to mount the rack in the usual place. So Lotus made up two bellcrank things pivoted vertically just ahead of the front wheels. A short rack was fixed to the chassis at one end and to one of the pyramids at the other. So when you turned the steering wheel the pyramid swung left or right on its verticdl axis. a simple link across the chassis moved the other pyramid in unison.
Then long steering arms ran back at about 45 degrees to the car centre line to the normal steering arms on the hubs.
You can see it in this imagehttp://img196.images...tus63frana1.jpg
Now the Lotus 63 was not a great success so be warned but I do not recall reading any big issues with the setering set up.
Why might it help?
- the rack is sprung weight
- the steering column does move slightly in and out but this is minimal and no joint of any kind is needed.
- The required rack is very short but this is exactly what some FWD racks look like ( e.g Citreon AX).
- Importantly the conflict of steering arm length to axle movement is transfered partially to a conflict betwen your longtitudinal radius arm lengths and the steering arm length
- So if you were to mount the two bellcranks near the inboard ends of your radius arms the conflict of arcs would be minimal or nil.
As your radius arms go forward this might be possble.
I am sorry the description is so poor MAYBE Tony Matthews has one of his master cutaways to hand which make it all much clearer.