Here is a tankless diving system that lets you go for a 45-minute dive at a depth of 12 meters. AirBuddy is portable and easy to use. It has a battery powered dive compressor that floats on the surface of the water and follows you as you dive. Just charge the battery, connect the hoses, and you are ready to dive.
According to the developers, you can set this up in a few minutes. AirBuddy is expected to ship in 2017.