Owners of retail buildings in the Reno-Sparks area are getting creative in their efforts to refill vacant big box spaces, subdividing large, dark retail spaces to land tenants. Examples include: • The former Mervyn’s building in Sparks, now home to Ross Dress for Less and Fallas Discount Stores • The former Longs Drugs in Sparks, now home to AutoZone and 99 Cents Only • The former Scolari’s store in Lemmon Valley, soon to house Big Lots! and Grocery Outlet. It’s a model that may crop up more often as the vacancy rate in big retail spaces — those of 20,000 …