Have you actually looked into using Crown Vic crossmember and suspension. The newer versions with aluminum parts are light, easy to mock in and many truck enthusiast love them for handling. And you can source COP CAR brakes and such. Also don't over look 88-94? thunderbird/Cougar rear IRS it narrows easily, and can be had with 8.8 heavy duty rearend. And if you plan accordingly you can add eccentric cams to rear adjustments and make alignment a snap.
Good luck. Also don't look past adapting in a GM front Subframe as you can upgrade to C6-up huge Corvette brakes then with Speedtech ATS spindles OR talk to Kore3 about adapting C6 stuff to Say Camaro style front brakes. Ad sub. If your pulling it apart, starting with easy to replace parts like big GM/Corvette brakes. And as for IFS the 8.8 has literally dozens of parts makers. Only issue might be hd a Le stubs but if not racing I'd bet Moser could whip something up and several companies build HD driveshafts I'd say they should be able to accommodate that rearend style if you talk to right people.