Our bathroom floor is lino but that was laid over plywood, as recommended by the manufacturer. If you want a hard floor, have you considered rubberwood? This is known in France as hévéa. You can get it in tongue-and-groove planks formed from blocks. We bought ours in the UK because at the time it was cheaper - also far cheaper than oak or bamboo. It is an overall goldy colour with attractive gnarly patterns in the wood and is hard as iron. You can use an underlay for sound insulation. We have this in bedrooms and landing and it looks wonderful. Some day we'll get around to installing skirting boards.