Can a wooden/fabric cover design be built of metal?
Ed Swearingen used to say that it made little difference if you build an airplane from wood, aluminum or carbon epoxy - in the end the weight would not be too different if the parts are designed well.

Note that many aircraft in the 1930s used the combination of an aluminum frame and fabric covering. Especially the control surfaces of many aircraft, but also the fuselage, wing and tail surfaces of the Vickers Wellington were built this way. Also, many gliders before the advent of fiber-composite structures used a welded steel-tube frame covered with fabric for their fuselage. Since glueing works better with wood, the fabric cover needs to be sewed to the ribs and stringers, so suction forces will not lift it up over an extensive area.

Key is the limited dynamic pressure: If you do not increase operating speeds, exchanging wood for aluminum will be straightforward. Only the torsion box of the wing would need closer attention, since the low weight per area of plywood cannot be recreated with aluminum sheet - the wall thickness and the resulting buckling strength would be too low. You would be well advised to add more stiffeners and ribs!