This is an interesting collection of raised bed gardening kits. Any and all of them could be sub-irrigated planters (SIPs) with some simple modifications.
The results would be in the range of 50% more fresh produce with a water saving in the range of 90%.
The key design components:
1. Water tight container. Line with plastic sheeting if necessary.
2. Water & oxygen reservoir(s) - corrugated perforated drain pipe, or inverted nursery flats or recycled plastic food container with holes punched in the tops and bottoms.
3. Overflow drain hole(s) when used outdoors.
Of course if you are a woodworker you can make your own but these kits are handy for time-short people who can afford them.
Here is a Flickr photo set showing very simple methods to make sub-irrigated raised beds and other types of sub-irrigated planters (SIPs).