Hello Seth,
If you are really wanting a Mac and are willing to purchase used hardware take a look at Swappa.com, I have been quite happy with the gently used hardware I have purchased from their users. With a bit of research it looks like the best screen for Epileptics is anything with a high refresh rate, current gaming laptops offer 120Hz refresh rate on their LCD screen. I found a relatively cheap 120hz Windows laptop Here on Amazon. I would keep an eye out for black Friday deals coming up as well.