Option A: Drill the hole, fill it with two pieces of brass, telescoped (so you get a 1/32" wall), split the gear. This has the disadvantage that the gear can pop out fairly easily.
Option B: Drill a hole, then file it out oval fore and aft (actually, along a line at right angles to the line of the gear legs -- but if that's confusing, just make it fore and aft, it'll be close enough). Make two landing gear halves that stick all the way through the fuselage, with about 1/8" hanging out on the opposite side. Each wire will need a little dogleg so that they line up right. This adds a lot more strength -- just the holes in the plywood, without any reinforcement are enough. It's harder to make, but the gear is far less likely to pop out.
Option C: Find some profile landing gear the right size, made out of sheet aluminum. Brodaks sells it (I think), or with a lot of inspired shopping you may be able to get the right stuff from Hobby King, made out of carbon fiber.