Well give me a nice curved piece of wild cherry--hard to find--but it is worth the hunt--the wood will after some use produce a wonderful smooth finish and just reek with personality, produced with your sweat, and the polishing action of your grip changing position as you work
you can steam bend a straight piece of cherry, but the true natural bent wood is best
My experience with steam bent wood is that it removes some of its natural composition and will feel differently when you go to use the finished handle--it will just feel and act dead so to speak
another approach is to take the green blank and bow it using sufficient force, heating or boiling just the area to be bent, this will soften the natural bonds in the wood fibre so it will bend without breaking
Some types of wood bend green better than others
Some people when it comes to handles swear by hickory, others white ash, and I am sure that other local woods depending on where you live will be the specie of choice--it will be interesting to here a take by others on this subject--I for one would be interested in hearing what others have to say