If you have a used office furniture store, check them out. I bought a 6 foot by 3 foot electric lift table and have been thrilled with it. I would recommend that you cover the top in “Ram board” ( contractors put this on the floor when working in your home so as not to damage your floor) and just replace the ram board when it finally gets dirty enough. This will keep your desk top in like new shape.
I have 2 office desks, and a pair of 3-draw filing cabinets, with an office desk top on it.
With a High-lift office chair, I can work sitting or standing as I see fit. Bonus for me, it puts my bench space at window height.
I’d sorta suggest you watch the news papers for auctions at closed down factories and even generic businesses. The place I worked at used to have one building that was the size of a Walmart with nothing in it but office furnature, book cases, and computer furnature. Every thing you could imagine under one roof. Heard they went in there and sold it for a few cents on the dollars just to get rid of it (most was like new).
They sell adjustable legs for benches, and all you need is a bench top from there. Lowes and Menards sell a wide piece of wood that is roughly 3/4" thick and comes in 16" thru 24" widths and lengths up to eight feet long. A typical modeler won’t need much more the four or five feet in length. Then buy a sheet of 1/4" hard Masonite for the top. When they cut it to your size, you’ll end up with a spare piece for a new top down the road.
A buddy who ties flies has a similar bench, but for legs on one end he uses a small book case (if your like me you have a ton of reference material) to hold up one end. The other end is a kitchen cabnet end piece with a little frame under it to get the right hight. Lowes sells them unfinished. Then on top of the book case he added another just like it with the bench top sandwiched between them. I’d guess his bench to be six feet long, and he’s got a wood tool box over the cabnet. Every time I drop by he’s got different lighting over it. I’m still using an Ott light. I’m going to build an “L shaped bench” similar to his. Probably six feet by four feet with the short side for fly tying. As much modeling stuff as I’ve aquired thru the years, I must have three times that for making bugs.