I love this thread. Using glue as a lens, awesome. What about using half a clear glass marble for lens? Perhaps it's possible to cast the glue in a mold.
What about this, if you have the right shape for the lens, why not make a mold out of silicone? Hobby stores have a kit to make a silicone mold from a hand in order to make a cast from that mold. Perhaps this stuf is acurate enough for making a mold. I don't know if superglue sticks on silicone, I guess not. But epoxy might work.