As was alluded to a few times, you can actually cut these products shorter if you desire. Sometimes, there will be indicator markers on them already. But, if there is not (or if you want them shorter than the marks go) you can still get around it. Before you begin, though, ensure that you remove the levers, grips, and bar ends. You will need to measure the distance from the center of the headset to each mark. To do so, sit on the bike seat and grip them to the width you want them. When this is established, take a felt tip marker and evenly mark the ends.
For a more precise cut, attach a clamp to be used as a cutting guide. From there, take a hacksaw and begin slowly cutting on the lines that you marked. Do so slowly for the best results. To finish, take a flat-file to round off the edges.