Coreboot has, in this patch, experimental Optimus support. I dealt with a T430S the other day, and these can sometimes have Nvidia GPUs in them. You can still use the Intel GPU, or make use of Optimus to operate the Nvidia GPU (rendering offloaded to Nvidia GPU, but framebuffer handled by intel GPU).
At the time I didn't have time to experiment with it so just shipped it with everything done on Intel GPU. The T430S I had was for a customer of my company. So: TODO: buy a machine that has optimus thing in it.