i think it could work. you need to assume, though, that the customer has zero equipment to begin with, or else you will be severely limiting your market. you need to be able to rent not only the stand and kettles, but also ferment equipment, provide sanitizer, fermentors, and some way to keg or bottle it. obviously you would charge for those things, but if you didnt have them available, it would exclude a lot of people.
secondly, you are assuming that people know how to use an all-grain, automated, large-batch system, which i dont think you should. i know how to brew on my setup, but if you ploped me in front of someone else's, i dont know if i could replicate a beer like i would normally be able to on mine. people who make fantastic small extract batches may be disappointed. there is a learning curve. perhapse you could have classes, or add "rent an instructor" to the price.
third- you will inevitably need to supply the ingredients. sure some people will use their own, but the whole reason spaghetti sauce sells out next to the spaghetti instead of in its own aisle, is because people are lazy. if they are paying you, they want this to show up at their house ready to rock. then you get into having to assemble recipes and instructions for people to use...
i really like the idea of opening a brew-your-own facility, much more than a "we-come-to-your-house" method where you dont know what resources you have availble when you get there (and so have to design it for the lowest common denominator).