Combine vanilla wafers, powdered sugar, cocoa powder, and chocolate chips in a food processor. Pulse on and off until mixture is finely ground.

Add maple syrup and rum. Pulse until mixture comes together to form a stiff, but moldable dough. If mixture is too dry to scoop and roll balls, add more rum, a little at a time, and pulse again, until the proper texture is reached.

Scoop out portions of dough and roll into smooth balls. The ideal size is between 1 and 1 1/2 inches. Place on a plate; cover with plastic wrap and refrigerate while you prepare the white chocolate coating.

Place coconut in a shallow bowl; set aside.

Place a heat-proof bowl over a small saucepan of simmering water over low heat. Reserve about 20% of white chocolate to stir in later; place the rest in the bowl, and let sit, without stirring, until almost all the pieces are melted. Add in reserved white chocolate, and stir until smooth and runny.

Drop a rum ball into the white chocolate. Use 2 forks to roll it around to coat, then lift out, letting excess chocolate drip off. Drop into the bowl of coconut; toss to coat. Using your hands, do the final shaping, pressing coconut lightly into coating. Transfer to a plate. Repeat until all rum balls are coated. Place the bowl of white chocolate back over hot water if it begins to harden.