From what I understand, the easy way would be make the 4.7 forward shift case you crawl box.  Put he 2.28 top shift case in back.  Then you would only have to tear into one case, the 4.7.  I don't see having a 4.7 versus a 2.28 2wd low range as a big problem.  All you would need is a dual adapter.  If moneys not a hugh issue, go with the twin stick.  I can't believe anyone would not be happy with a twin stick.