My suggestion is to downgrade that house. 5000/sqft is enough to house 5 families of 5
In all serious tho: The 'standard' go-to router is the Asus RT-N16, but I'm not sure its going to fit your 'commercial' grade needs. Lets be honest, 16 port switches, multiple AP/Repeaters...You really should go commercial grade, which is above my level of expertise in choice