This is what you are talking about. Not a Sals but a HD front diff housing that takes a rover type diff centre.
Printable View
Not Shortened, but the Civvy version of the 6x6, which has the standard track front end. Like THIS.
If you still want a Salisbury front end, they regularly appear on UK E-bay, but shipping is a REAL killer.
Land Rover Heavy duty front Salisbury Axle complete kit RHD | eBay
Land rover defender salisbury front axel rare | eBay