I recommend The Company Store or Garnet Hill.

Try Dash and Albert

Indoor/outdoor runners

http://www.lowes.com/SearchCatalog?catalogId=10051&identifier=Runners&langId=-1&storeId=10151&N=4294856541#!&N%5B%5D=1z0zeb4&N%5B%5D=4294856541

Amazon has a dark gray one: http://www.amazon.com/dp/B00Y5C0OIM/ref=twister_B00RQVO83G?_encoding=UTF8&psc=1

2x8 is hard to find in a machine washable rug. It would be much easier to find two 2x4s in your colors. Are you open to a runner that could be washed outside, vs. machine washable?

http://www.amazon.com/Striped-Braided-Durable-Outdoor-Washable/dp/B00L4JHPV8/ref=sr_1_1?s=home-garden&ie=UTF8&qid=1434431056&sr=1-1&keywords=yellow+gray+white+2x8+washable+runner

Thanks everyone. I was worried that polypropylene might not be comfortable to step on out of the shower but the braided one might work.

Also in 2'3" x 7'6" Plow & Hearth has a great selection of indoor/outdoor rugs.

http://www.plowhearth.com/710-x-1010-laurel-indoor-and-outdoor-seagrass-look-rug-in-neutral-patterns.htm

Braided in different colors:

http://www.plowhearth.com/8w-x-11l-braided-rug.htm

2' X 7'

http://www.plowhearth.com/9-x-12-houndstooth-polypropylene-indooroutdoor-rug.htm