Hi jim13, welcome to Outdoorking.
There are a few things that are made more difficult by using stainless steel: it is more difficult to drill or otherwise machine, to fold or bend, and to weld. Remember that some welding is necessary on the solid deck, in particular. I'm not saying it can't be done of course, I'm saying it would be quite a project to do it and end up with it looking good: paint can cover a multitude of sins.
On the other hand if you put in the time and effort to somehow execute it nicely, you would certainly end up with a very unusual and widely admired SB45.
