I made them with my Girl Scouts years ago, but I think we just used jello...like thicker jello jigglers. I'd try 2 tbsp gelatin to a cup of fruit juice.
Last summer I tried zucchini gummy worms...strips of the meaty part of the zucc, 1 can 100% fruit juice concentrate and a can of water, simmered until the zucc was transparent and then tossed in the dehydrator. They were really good and no one could guess what they were. We used cherry-apple, raspberry-apple and grape concentrates (the grape tasted like, well, raisins, lol).