[jonathanstrange]

Not important, but I want to briefly point out as a Grammar Nazi that you mean uninhabitable regions. Inhabitable and habitable mean the same and their opposites are uninhabitable and not habitable. This is one of those bizarre oddities of the English language.

[lloeki]

Just for kicks:

    English       | French
    --------------+------------
        habitable |   habitable
      inhabitable |   habitable
    uninhabitable | inhabitable

[ashoeafoot]

What have the natural romanic languages ever done for sus?

[ashoeafoot]

would ainhabable or antiinhabable be correct ?

[sandbach]

No.