pull-out shelves that you can step on to reach the top! Garage shelving idea: the lower shelves actually glide out so you can step to reach top shelved items. Then they slide back to the wall. This would be so easy to DIY!
basement stair cabinets, stairs with flip up steps and very narrow stairs. Each step goes up one at a time for each foot. It is sort of spaced so you are putting one foot per step with a steeper step. Very space-saving.