A total colostomy is radical, radical, radical. For people with REALLY bad C, I think a partial resectioning is sometimes done; by shortening the length of the intestines, stools don't loose so much water and can come out more normally.
Of course, if you are ever prone to D, your D will become worse for the same reason--the body not absorbing enough water.
Anytime you do something like that, you will have take vitamins the rest of your life because you will not be absorbing all of the vitamins that you need.
My mother has a cousin whose stomach is so slow to empty that she pretty much has no function. She also has terrible C because of the rest of her GI tract is really slow. The last I heard, they were consdiering doing gastric bypass surgery on her to try and shorten her GI tract enough that it will function at something like a normal rate.