This Lift & Slide cart is a clever bit of design. It combines a dolly with an undercarriage scissor lift that can be slid out from beneath the dolly.
The arrangement allows you to wheel heavy items over to the bed of a truck, load them into the bed effortlessly, and then slide the cart in along with the goods:
Unloading is similarly simple:
The prototype shown here was developed by Oregon-based Pairon Solutions. They say a Kickstarter will be forthcoming.