Thinkpads. Thinkpads have good build quality - they pass more military toughness tests than 'toughbooks' do, and they're generally 'just work' when it comes to linux (sometimes you'll need a broadcom driver or similar if you're using Debian)
Some plastics are very durable, and the type that comes with the thinkpad is not the cheapo dell plastic. Regardless the plastic shell isn't designed to provide structural strength in the first place. The inner frame is the core strength of the thinkpad; magnesium or some kind of metal (I forget exactly).
Please provide links for your claims of suffered build quality... if only for my sake to perhaps look at other laptop manufacturers.