Deane, I have had great success with a music stand and a gooseneck connected to my iPad mount, the great benefit being I can curve the iPad in over the keyboard and thereby bring it closer.
Putting a gooseneck in your design might help you too. Just a thought...
_________________________
Graham, Korg Pa1000, Korg G1 Air, Countryman E6, Roland BA330, 2 x Roland CM-30, , Mackie SRM150