Well I'm just plain envious. I wouldn't know where to even find scrap that size to build a stand. My 3T sits on the end of the bench with just enough sticking out so the bucket underneath with the old towels can catch the broach.
I'm with @6.5 Fan . You won't believe what you can find at farm auctions. The sale price is very often the highest that a scrap metal guy will pay given the cost of getting it their yard and the need to make a profit. Buying it at their yards is also a possibility but the cost sky-rockets. Thick plate, thin plate, beams, box tubing, bar, spring steel, soft steel, hard steel, castings, forgings, etc etc - it's all there for the bidding. Sometimes you can even meet a farmer at the auction with his own scrap yard..... "Jezz, I only want this cuz I need that 1/2 inch 6x6 box beam to make blah blah blah." You might be pleasantly surprised when he says to drop by his farm, bring your torch, and get it off my land before winter comes.