I haven't seen one. I know you asked about a step tiered system, but if you're looking for a way to save space, there was a mast design someone on here did with hooks to hang kegs on. If you could design it where the base came off or folded up, I can't think of a more space-efficient solution. I can't find the pic of the stand I'm thinking of. I'll keep looking.
I am using the one linked to above as a model for my build. I emailed the guy who built it and he send me some ideas. I'll let you know how it comes out
There was a three tier, fold-up, stepped brewstand someone was getting ideas on a few years ago. It folded flat and it looked like any other stepped brewstand when extended. It was actually pretty cool, but I doubt if the owner is a member here anymore.
I'll see if I can find the thread, but with our search function here, it may be difficult.