Like all previous options listed below, this one has advantage and disadvantages. The partial capo by Shubb allows the fingering of strings D, G and B and if you place the capo at the 2nd fret, you have an open tuning which is an isomorphism of the DADGAD tuning. It allows you this particular tuning while retaining the ability to form scales as you know them higher up the neck. You are severely limited however with what kind of tuning you can get.
The partial capo by Third Hand Capo however is more flexible and you can even place more than one on the fingerboard to obtain a wide variety of alternate tunings. You also retain the possibility of fingering scales as you know them higher up the neck.