The first thought that comes to mind is an industrial machine. That could certainly handle it. But they take up a lot of space, and they are expensive.

If you want a home sewing machine that can handle upholstery weight fabrics, I'd look for an older Viking that features the low gear. I have the Viking 6460 that I purchased in 1978. The low gear feature is awesome. The newer machines don't have the low gear, so I will always keep this one.

Upholstery is so easy and fulfilling provided you have the tools to optomize your efforts. After upholstering several projects, using a "home" machine, I located an old (1938)Singer 31-15 machine at a dry cleaners that had offered clothing repair services....$40 in the Pittsburgh PA area in the late '60s.

In the 80s, I got an almost new walking foot Consew 226 for $500. I had this machine geared down to a slower speed, as it is easier for me. The walking foot is especially appropriate for velvet/pile/thick fabrics.

Both of these workhorse machines are in heavy tables. Like many sewers, I use an adjustable office chair for sewing ease...and an old pingpong table for cutting fabrics.

My favorite home machine is a 1976 Viking(64-40), that has the low gesr setting. It cannot compete with the industrial machines in ease and quality of stitching for attaching welting to velveteen cushions, for example.

When I got the industrial Singer, I had it in our bedroom on my side of the bed. I sewed on it when DH was at work. Now, both industrial machines are in our lower level where I have a generous space for all my machines and projects.

If you are serious about upholstery, there are some great older books that none of the newer ones can touch in breadth/quality.

Also, consider getting a small air compressor and a pneumatic stapler and a pair of professional scissors to save your hands. I do not have any electric scissors, and would have to test them for cutting Italian tapestry and velveteen. My DH constructed my 'horses' and they double in the woodshop for my projects there, I covered the top bar with carpet scraps.
For me, the return on investment in these tools has been superb financially and creatively.

Good luck-you can do it!

I am planning doing a love seat and I intend to use my treadle, as I know it can handle it. And it give a whole lot of control over what you are doing.

Actually a treadle is a great idea. A lot of those older (pre 1950 or so) machines can handle heavier materials than newer machines. I used to sew winch and hatch covers from sunbrella on my hand crack.