I am probably a bit late in my reply and a lot of information has already been put forward but here is my two bob's worth.
An article I read a few years ago said that chemical softening of wood weakens the wood because of what it does to the structure of the wood.
I have done some steaming, first using just a kettle and dipping the plank into the boiling water for a few minutes , then moving on to making a simple jig out of steel down pipe adding a shelf of wire mesh to sit the plank on, see photos.
I have experimented with steaming several different woods, in my opinion hard woods will take a more severe bend probably due to their long grain structure though even soft woods like Huon pine will bend very nicely while still hot the key being while still hot.
You may have minutes to work with large pieces of wood due to it's thermal mass, small planks take seconds to cool.
Personally I would try some Beech I wouldn't be surprised if it worked quite well.
Hope this helps.