We still have an old treadle Singer, although it's electric. My wife and kids still use it as a straight sewer, it only has single drawers each side, but we used to have one with 3 drawers per side.
My younger daughter is a dressmaker, and she has a commercial Singer overlocker from the early '70's. It's a serious machine, with a 1/3hp motor, and the overlocker itself would weigh as much as an Airhead engine....I can hardly lift it. She moves house a lot, and I dread having to do the singer overlocker. In some ways it's not as good as the cheap lightweight modern ones (like ours) as it has curved needles - but like the treadle singer does what it does really well.