Maybe you have ever noticed that Andy McKee or John Mayer regularly tune some strings above standard tuning.
If you would like to try this yourself, be aware of the fact that the tension in the strings and the neck of the guitar goes up too. It shouldn’t be a problem to tune up one or two strings for a song, but make sure that you tune it back after playing. This prevents warping of the neck and the top. Please note also that you might break a string. Also keep in mind that sometimes your string might break. The guitarists mentioned are using other kind of strings than you do probably, and sometimes the construction of the guitar is adjusted to the higher tension.
In the video you see Masaaki Kishibe playing his song ‘Hana’. His guitar is in open D tuning (DADF#AD).