A few semesters ago I worked as a groundskeeper for a large estate and was asked to take down a large tree that was leaning towards the house... With permission, I was able to save a few of the log rounds , and I split them into neat, rectangles, about the size of two clothing boxes on top of one another. I stacked them in my mother in laws shed, and let them dry for a few years.
The tangled grain of ulmis rubra or slippery elm creates a very strong grain structure that is bad for splitting maul's, but good for wide, thin chair seats. The stool took about a week of messing up and wasting wood to get it right, and I could probably do the next one in just a few days. I used both a chainsaw wheel and a carbide carving disc on an angle grinder that I purchased here http://katools.com/. Sand paper flap wheels for the grinder, and curved cabinet scrapers helped finish it up nicely.
A length of some 8/4 maple for the legs, and the wedges, and a sprayed coat of clear Laquer were the only other materials needed. No metal fasteners, just wedged through tenons in the seat and epoxy in all the joints. I like how graceful it turned out, and with a quick comparison to the other options out there- http://www.dwr.com/product/tractor-stool.do , and http://www.thosmoser.com/category/stools/product/218/high_stool/ I think I saved about a thousand dollars making mine over purchasing. It was my first creation with legs ( with the exception of my 2 month old son Evan ) and I am very pleased with how it turned out. And who would ever guess this stool seat was once bound for a stack of firewood!