Clicking through the parts list, somewhat wildly <10cm inch 2k displays appear to be available for <$50 now. After a quick look I can't find much north of that in terms of resolution, but surely there has to be _something_ between this and the SOTA 4k+ displays going in high end headsets. If those exist then the last major barrier I can think of to DIY is the magic lenses required to make those screens viable when <50mm from an eyeball.