Water emulsification has been around for a while. Caterpillar at one time bought the rights to such a system and tested it quite thoroughly. It made a big splash in the trade magazines at the time and then ..... sort of disappeared from the scene. I don't know if the system you are talking about is the identical system Cat tried to make work, but as I recall it did require some engine modification and the emulsified product was a lot more than just pump in a few gallons of diesel and top it off with a few gallons of water along with the emulsifier and drive away. It was pre-mixed and the solution was not to be allowed to sit for extended periods (over 30 days I think) or it would separate and really make havoc of your fuel system. The filters were obviously different as well. Keep us posted on what you decide to do. It should be interesting.
If it were me, I'd ask for the company wanting to use your truck as a test mule to guarantee it. It breaks, they fix it for you.