Any laptop can be made more secure, but if you want to run a Linux-based solution like Tails or Liberte, the higher end ones will tend to have less compatible hardware, like UEFI (well, that's most laptops these day), wireless and graphics cards that require proprietary and/or Windows drivers and so on. If you want to run a Linux-based solution, Lenovo laptops tend to work really well out of the box. Also, I believe eddiethegun is selling a preconfigured laptop on SR.