If you don't mind sleeping on seams (I'm assuming they are smaller than a bed). Your bed, your sheets!

Are your old tablecloths real linen? The word "linen" gets applied to so many things that used be made of linen, but are not actually linen. Are they commercially made tablecloths? I have never seen an actual real linen tablecloth. I am sure that they do exist, but not real, real common, and, they would be quite expensive.

If you search for linen tablecloths on Amazon you will see them described as "linen tablecloths, all polyester". Make sense? NO.

You can buy some linen at Joanns. Most of it is wide, but you would still have to piece the lengths. If you watch for a 60% coupon, it might be worth your while.

If you really do have real linen tablecloths that you do not want to use on the table, by all means, do something else with them. Be aware, though, that most bed linens, table linens, and bath linens are not actually linen, unless specifically stated as such. It is just an old and outdated terminology that persists in the marketing world.

The seams, no matter how flat you make them, would bother the heck out of me in bed. There are may sheets out there to choose from.