In a CSA wins the CivilWar scenario, Missouri is a very real possibility, together with all of the other border slave states which stayed in the Union. Kansas is very unlikely, as are most other farm belt Union states, because slavery is not likely to be adopted very well to these economies. I dobt the CSA would want to add any states which might come to favor emancipation (either locally or nationally). I suppose the possibility exists that a very victorious CSA might conquer former US states as occupied territories or colonies. In this case, one might imagine a wholesale spread of the CSA into the Mountain west and Pacific to take control of the gold (and later oil) deposits.