As far as I know Mimosa will only grow from a root cutting, you treat a pencil diameter section of root with fugicide/hormones and then plant it just deep enough to cover it in your propagation mix and it will throw up suckers in a month or so.
I like that idea of hydroponic Mimosa, I see no reason why it wouldn't work. In a media based system that is adequately aerated rot should not be a problem. There are many commercially available inoculants available that are suitable for hydroponics or aeroponics.
I have a batch of baby Mimosas so I'll whack one into a passive hydro system today. I've been looking for a project and that's the one.
Aeroponic Mimosa would be perfect, the rootzone can be controlled for moisture levels to a very fine degree and the plants would grow at an astonishing rate (I'm assuming - based on observations of other plants grown aeroponically). Harvesting roots would be a breeze.