Why do you need any clear space at all ? The 'trend' for the last 30 years has been to have basins that protrude slightly forward -- yes , I know , there's arguments for and against , but basically if you have oval basins , there is space to have liquid soap dispensers or whatever other accessories you want , even if your vanity was say 1200 x 300 -- theres no taps , so I actually think your vanity sounds a bit too big visually ( or the basins too small , although at 550 any bigger would be classed as a bath haha ! ) .

Yes I have Polytec laminate in both my bathrooms, powder rooms and laundry. Our home is nearly 7 years old, and the laminate is still looking good. Most vanity’s have quartz or stone tops, have you asked the supplier to confirm your thoughts about being too heavy for the floating vanity? A photo of my children’s bathroom.

Looks like a version of a floating shelf. One for the vanity and one for the towel shelf. Its framed up and then boxed in. You can find similar DIY on Pintrest via https://pin.it/3hio07M or search DIY floating shelves. Haven’t seen them commercially available in Australia, would need to be a custom job.

Harvey Norman are distributors for Timberline vanities which may have what you are looking for - see link. If you see one you like online, you can go to a HN Bathroom store and they can order it. https://timberline.com.au/