Very nice. It looks beefy. BTW, it's a good thing you guys aren't building boats or airplanes...they would be way too heavy to float or fly.
My own South Bend 9A is lighter than this lathe, but it's on the table it came to me with. I think it's been on the same table since the factory that bought it had it in the 60's. It seems to be a shop-made affair. It has a 2X4 wood perimeter frame. The top is .142 thick steel screwed to the frame. No other reinforcement. Steel legs made from angle stock about the same thickness hold it up, and are screwed to the frame. There is no other structure at all.
Since I've had it, I added heavy duty casters. Everything in my shop that can move needs to be able to, since I'm really tight for space. Since it moves around to where I can use it when I need it, it isn't always dead-nuts level. This has never seemed to be a problem. Of course, I'm working in .001's, not .0001's.
In fact, lathes like mine were installed on Navy ships. Ships underway move around constantly and are pretty much never level. I've always thought people get excessively hung-up on leveling lathes.
So, I think you have some overkill going on. Better too much than too little, though.
-Ed