I’ve had a look at your website and find your comments about the G5 underwater housing very interesting.
Are you aware of any filter lenses available that would fit the housing?
When using my Sony DSCP5, I always carry an orange filter lens and find it quite helpful for all shots taken in non-macro range.
You can check out some of the stuff I took with the Sony at this address:
http://www.totalidea.com/files/visioncare/Photos/Fiji2004PlantationIslandDiving/
Bearing in mind that I am a real amateur, just starting with underwater photography, I must say that the Sony has done an acceptable job. However, because of the less than poor battery life, I always wish I could take my Canon G5 with me.
I think I would buy the G5 undwerwater housing, if I could find an accessory filter lens for it.