We just released a new set of buttons named "Bubbles". In this case the buttons are in SVG format, so the user can select the size directly inside the Pano2vr skin editor. The buttons are semitransparent and we provide the full set with icons in black and white (the user can edit and change the colors using a text editor or an SVG graphics editor).
To buy the set or to see other sets, you can visit our skins site http://skins.360panotours.com
Here a sample of the new set...