Paul,
Thanks for your help on this. To confirm, there is absolutely no magic in the 24v pack -- although of course, there are differences among battery packs, they are slight and the good ones are cheap. Soneil is a great charger and you can buy it elsewhere.
This technology is used in all kinds of machines and safety devices with chargers from various manufacturers. We had one over-heat and panicked to put them in steel boxes, etc. Gary is no longer producing these.
We will probably self-source for the next-gen but likely keep it a kit as we can't be responsible (financially) for the performance of parts provided by others (ie. battery + chargers). To keep this absolutely clean from a liability standpoint, you will need to do final assembly: they'll be yours.
Seth