I ordered my multifiber fabric by phone from Testfabrics in Pennsylvania, after requesting their printed catalog and a current price list.

The stuff I have has a polyester warp, and the weft consists of 1/3" stripes of diacetate, modacrylic, triacetate, bleached cotton, Creslan® acrylic, Dacron® 54 polyester, Dacron® 64 polyester, nylon 66, Orlon® acrylic, spun silk, polypropylene (polyolefin), viscose rayon, and worsted wool. It's about four inches wide, many yards long, and came on a spool.

The closest I see on Testfabric's Multifiber Fabrics page now is MFF#43. It's not quite the same, but it's certainly close enough. It has all of the fibers I'm interested in. They have other multifiber test fabric choices, as well.

Be careful to keep this stuff sealed up in plastic when not in use, or however you protect your wool from insects. After leaving a one-yard cut loose in a drawer for a year, I found that moths had eaten much of the wool section.

Testfabrics also sells some blank dyeables, such as silk scarves and cotton napkins, aprons, and tablecloths, and all sorts of undyed yardage.