I would second Fishindude's suggestion, although I will say you might have a hard time finding a structural engineer willing to take on your project. Reason being the materials you are looking at using (plexiglas mainly) are not materials most structural engineers would be comfortable dealing with. The anchoring into concrete would be child's play for any structural engineer worth their salt, and stainless steel is close enough to the more typical A36, A572, and A992 we deal with all the time that it shouldn't present issues.
I have designed an indoor plexiglas platform for a clean room, but no other structural engineers I know have dealt with the material. Personally I would be somewhat concerned with using that material due to the combination of UV exposure and chlorine/bromine. Any UV coating would be useless since it would be scraped off with that application. There might be an acrylic blend of some variety that would be ok to use for these...I'm not really familiar enough with the material to know but I suspect there would be.
The only industry that comes to mind which would have people that are very familiar with that material for structural uses would be the aerospace industry. So if you happen to know a structural engineer retired from Boeing or similar, you will be in luck! If not, best of luck finding someone. We do occasionally get calls at our office for people looking to do smaller oddball projects like this and we generally farm them out to a few people we know that used to work for the company. So perhaps calling around to some smaller structural engineering firms will get you some options.
