I'm currently creating a lot of drumtracks for existing songs. I try to find the drumstyles that are most similar (at least the "feel") to the original. For the endings I do a lot of experimenting with rests, shots and changing the number of counts in the last bars and even changing the (sub) styles for the endings. This often gives a suprisingly nice result.
Also the solution Rachael uses seems like a good way to go.