That sounds very similiar to my welding table. I used 1/2" steel for the top, found an old
ROPS from an old D9 dozer to make the legs from. Think they are about 5" square but at least 1/2" thick walls. I cut up the tongue from a mobile home for my cross pieces for the frame between the uprights. I think it was about 12" or 14" tall and made a great frame. It is very heavy but I can prob have my skidloader on it and it won't move or collapse.
One thing I did that my neighbor (full time heavy equipment mechanic) showed me on his was the height, it is 27 1/2" to the top of the table. I'm glad I went with that height, when you're working on something it is almost always the perfect height now. Most everyone builds a welding or working bench too high. Another thing he talked me into was making legs on one end shorter, I then put 8" hard plastic casters that do not spin around under those shorter legs. I just slide a floor jack under the end with full length legs and raise it to move the table around to where I need it.
Nothing like having a good solid bench to fabricate and weld on and not worry about it moving around or collapsing.
Topstrap