Here is a kit that lets you build a Raspberry Pi robot capable of carrying you. The Magni has 2 X 200W hub motors, Raspberry Pi 3, and up to 24 hours battery life depending on the batteries you choose. It runs ROS Kinetic on Ubuntu 16.04.
You can program these robots to carry your things, bring you a drink, and do a whole lot more. This project is getting funded on Indiegogo.