The Lil' Goblin is a mid-powered rocket. I thought the idea was for something low-powered. The Mini Cowabunga and Mini Squat come closer, but they're still 24mm.
It's hard to find a suitable commercial kit for this purpose. Closest I see in fiberglass is the Mach1 BT50 Patriot.
Or, something like the
Estes Chiller would work. Plastic fins, should be durable, probably 250' on a B motor. 19.4", not *too* hard to pack, especially if you take off the nose cone. You could even take off the fins for shipping (they just snap in), although I don't know how many times they could be swapped on and off before they start to suffer.
Hey, you wanna do something really spiffy? Custom-cut some foam for the shipping box, which will travel with the rocket and keep it safe. That'll eliminate the need for the shipper to "reinvent" the packaging each time.