I was wondering the same thing myself last night. My experience with "wings" and $tree foam board is that if you remove the paper it is to soft and weak, not at all like depron or blu core. If you leave the paper on its quite heavy, about 120 grams per sheet. It becomes difficult to balance wings when the paper is left on since most of the weight is behind the CG to start with.
So my idea was to modify the Micro slope stick
By enlarging the plans 125% to give it a 30 inch wing span. I used hot melt glue for everything. An arrow shaft that has been laying around for years made the stick and an 1/8 inch carbon tube was glued to the underside of the wing at the crease. It weighs 6 ounces using a couple of spectrum 7.5 gram digital servos and a 7 channel Faast reciever and 280 Mah battery. Just stuff that I had laying around looking for a home. I improvised a "pod" to go around the arrow shaft in the front. Calm wind have prevented me from trying it out on the slope but a few side arm launches has shown it to fly OK.
If you build a "wing" keep it light in the back! Better yet learn to hot wire and cut your own cores!