Cat tree Maine Coon Sleeper Blackline Dark Grey has 20cm thick posts and a mega executive chair with cushion. You can buy the Maine Coon Sleeper scratching post at Cattreeking.co.uk
Cat tree for big cats Royalty Crown is a very sturdy RHRQuality scratching post with its 20 cm diameter thick sisal poles and weighted base plate of 60x60 and 4 cm thick.