If your navigation bar uses them, you can also specify its tint color (with the TintColor key) or the name of its custom background image (with the BackgroundImage key).
Many paint manufacturers have produced pre-selected color palettes arranged by architectural style or color range that specify compatible field, trim, and accent colors.
The twist is that the recipients are notified of the gift before it ships, and they can then specify preferences like size and color, or even select a different item.