Here's two models that may have had some Pigasus influence in their designs.
Dick Stafford's Cochon d' Eau (French for Water Pig) is a water rocket.
The wide bottle fits the pig profile well. He built it for his grand kids.
Tom (Babar on TRF) posted pictures and a video of his Squirrel rocket.
It was stable on B6-4 engines but might need nose weight for C6-5s.
The TRF thread and video is HERE
Both great designs!