The Akasa Bean Canyon NUC case is now available as a complete system, thanks to our friends over at Atlast! Solutions. They came to the same conclusion we did : "We recommend the vertical standing position for the PC, as this aids airflow and cooling. The 4 feet can optionally be used on the base to enable horizontal standing." The i5 version is available from 800 euros while the mighty i7 iteration starts at 922 euros.
Update: Also available from Quiet PC, as a case or a complete system.