Take a long stretch of para-cord and double it over itself. Attach the bent end to something immobile, then put the two loose ends into an electric drill/screwdriver (where the bit would go). Then wind the cord until it is very tight. Tie the two ends together. Coil.
You may now attach the two ends to any two objects so that it is stretched taught. The twist on the para-cord will be tight enough that you can simply pull them apart, and stick a corner of a sheet or a bit of sleeve into the cord, and it will hold it without needing clothes pins. This will work smashingly for camping as well.
When I was living on a sailboat, we did a variation on this. We just used a standard 3-ply poly rope. Twist it against the lay, and a small opening would appear. Tuck a corner into the opening and let go...it would close itself, and hold the clothes. Don't expect good results on a very windy day. We looked like a Chinese Junk on laundry day.
I dry my clothes in a shed/greenhouse built for drying my firewood. It has good air circulation and some solar gain, but no wind. I just drape the clothes over the line. For clothesline, I use bits of orange nylon strapping that I scavenge from the lumber yards.
Justin Rhodes 45 minute video tour of wheaton labs basecamp