The little-known South African bulb Ledebouria zebrina sailed through our winter (single digits F) without a scratch and looks great right now.  Ledebourias are cousins to the more popular scilla, and this one gives a wonderfully tropical look to the garden.  The back of the leaves are striped like a zebra at the base (hence the name).  We have not idea how far north this might be winter hardy, but welcome your feedback.