I am working on a series of stools in a modern rustic style. Finding some good, straight grained ash has been a real challenge and generally by the time the timber has got to the sawmillers it is too dry and too expensive ! I have found some nylon webbing on ebay which comes in some great colours and is immensely strong, ideally I would love to use Shaker tape but it works out as too expensive for a simple stool.
Here is a similar stool, also in ash but this one has an Irish style woven seat. It is very quick an easy to weave and smells great. I am pretty sure it is hemp which I bought years ago and kept in stock. The only down side is the weight of the rope, maybe there are some lighter ropes and cords out there ?