For me, realistically, it'd be a 10x3x3 with a 6x2x2 sump.
Id have 2 islands of large bogwood with some smaller rock work with a natural sandy substrate with large open spaces for swimming / bottom dwellers.
Id have a large k1 moving bed compartment in the sump with plenty of jap mat, oversized UVS and all Ecotech Vectra, Vortech, Versa and Battery Backup systems.
Stocking wise would be all South Americans for me, including my Oscars, Rotkeil Sevs and Geophagus, but id also add a True Parrot Cichlid, Black Diamond and a Pearl Stingray (My grails).
One powerball.