I just receive 2 links from Steve Lange (slopeaerobatics.com) about videos demonstrating what can be achieved with an Ultra light "MasSwissFish" at only 470gr, and a Big Fish at 685gr. Both are made from EPP and laminated film. They are derivated from the original "Le Fish".
Both video are just incredible. Given that the cam is a GoPRO HD with a fish eye lens, you can imagine how close Steve and Peter fly. What is also very interresting is the low speed, and the hability to do rolls and loops at that speed.