Where can I buy a cone of Banksia Laricina?

The Rose Banksia is native to a what is now a conservation reserve in W.A.between Kalbarri and Moore River. As far as I know it is rarely cultivated - so I don't know how easy it would be to buy a cone or the seeds.

You could try:
The Banksia Nursery or the Australian Native Plants Nursery - both online

If you were to grow this shrub it would require a Mediterranean climate (i.e. wet winter, dry summer) and sandy soil to do well. It would be difficult to establish in areas with humid summers - just like most banksias.

Be careful sending live plant matter to Europe there are all sorts of rules and regs. about what you can, and can't send.