Programming from scratch...unless you can play manual drums..very well...DON"T start from scratch...Use a drum pattern that exist...you can use multiple drum patterns from existing patterns..

Actually this holds true with the other parts of a style..It would be much better morphing the styles as a blend for a new style...The next best creation would be "punch in" recording sections for changes in the existing style..

As mentioned ..there are so many styles found..that just changing instruments or dropping parts of an existing style can do wonders..