> After searching the archives for options for producing hot water on
> demand without having to install a gas heater, I have opted to try Dave
> Garth's ingenious design.

Steven,

I was thinking along the same lines myself.  Found this chap in Sydney,
Australia who makes the unit your thinking about!

The heat exchanger is $165 Australian, shippping to US $41 Aust.

Engine RPM 1400...will give you 5 litre per minute shower at 48 degrees
C.

You can write them at:

TWINE 4WD & HOT WATER SHOWER
John Twine
36 Whitegates Ave
Peakhurst 2210
Sydney NSW
Australia

Phone (02) 9533 2491
Fax (02) 9584 9983

Cheers,
Chris Gibbs