I bought Takumashi, my Nishiki Citisport, with wide riser handlebars and cheap black foam grips. I kept the riser bars for a while for two reasons... first, their width came in handy as it matched the width of the Basil Kavan panniers I had on the back. I figured if I had wide handlebars, I'd be less likely to ride into spots that were too narrow for the bags on the back. Second, I believe that a semi-upright position is better for me on some bikes. Some weight on the hands seems to translate to more responsive steering and a little more agility.
I'd seen references to twining handlebars on Lovely Bicycle and one or two other spots, but I had not read enough to make this more than a shot in the dark. I used ordinary garden twine, the stuff I use to tie my tomato plants to the stakes. Here's a look at the grips up close.
First, let me say that I know the wrapping job is imperfect. In fact, this was only going to be a trial run to see what I learned about wrapping, tying off the loose end, etc. But, when I was done, I was fairly pleased and seriously doubted whether I'd do as good a job the second time around. Besides, the knobby "mistakes" toward the end of the grip actually help -- they give a little extra grip to my hands when I'm riding uphill or just trying to find a bit more speed.
When all was said and done, I liked the result, as imperfect as it was. I didn't want the twine to look too precise. The color and fraying twine give it a kind of organic, bamboo-ish look that I like on my Japanese bike.
Some shellac on the twine to solidify it and adhere it to the bars and I was done.
For a far less random, much more clearly thought-out primer on twining bars, see Lovely Bicycle here.