The japanese company Inon just announced a new waterhousing for the Panasonic GF1. It has a corrosion-resistant aluminum alloy body (diving limit is 75m). You can use the Inon compatible flash (Z-240, D-Series 2000, S-2000, D-series 180, Z-220 series). And all Panasonic lenses are supported. The full kit price (with grip and lights) is $2,200!