My best friends mom would always use twin size flat sheets. The family was large and they had a banquet long table. Some quality of sheets are thicker.

I've had some light weight colored denim. That might work.

How wide were you needing?

Should be in home decorating. I got some fab pieces on craigslist. LLDS!

Where are you? Jo Ann fabric has it, but like capoodle says i like to use flat sheets, i go to a discount store and they have them very cheap.Anna has very good prices!

Uphoistery fabric is heavier, but it only come 54" wide

some curtain fabric works well to, depends on what you need

There are places on line that sell Tablecloths in various sizes and offer different types of fabrics in them at very reasonable prices.

Do a search for Table Linens and see what pops up!
May save you sewing time!

Also some Quilt stores on line offer extra wide fabrics for backing quilts that may be a place to look also.

EastWitch2

Just thought of another source that could be available in your area. A curtain panel. Sometimes the clearance has just one panel for a good price.

I'm with Capoodle...flat sheets are great...inexpensive, washable, long wearing...totally available. I have even used them for Duvet covers that I slip a comforter in and they work really well with cutwork designs.