I've just put together a system using the Rule 500. Things which people would probably like as options would be a bronze thru fitting rather that just the white nylon. It looks much nicer and is more appropriate for wooden boats. I bought mine through the West Marine website.

If you supply sufficient hose to allow for making a loop, then you don't need a one-way valve.

Heavy duty velcro is one option but sand will trash it and perhaps a way of using a couple of nylon web straps, at least for the battery which will come out a lot more frequently than the pump could be worked out. Maybe using cable ties attached to a bulkhead and then running a nylon strap thru the cable tie would work. I glued the bottom piece of the pump in the boat. The working part is removable and solves the velcro and sand problem.

As far as the battery charger is concerned get one that can be left plugged in without killing the battery. I got a waterproof(allegedly) rocker switch (West Marine again) which I attached with heavy duty double sided foam tape. This allows moving without drilling holes. If you don't have a good waterproof area to place the battery then a waterproof box with provision to run the wires through is another possibility.

I had to put this all together from at least 3 sources. I'd pay up to $100 for a well designed package including the bronze thru fitting and charger. I would have gladly foregone all the time I spent on the internet if I could have.

How big the market is much tougher. People on this board are pretty safety aware. The general public wouldn't understand the importance of the pump. Outfitters retailer/renters buy a lot of boats but I don't see most of them installing pumps because of the maintenance issue associated with keeping them charged and functional. You might contact some boat manufacturers with a good design and sell direct to them. That might be the biggest market since they could advertise their safety awareness making it an option. They could also make trivial adjustments to accomodate the thru fitting and battery holder.

Mitch