Now that we talk about 4k... Lately I've been wondering if the next thunderbolt display would stay at 4k instead of going 5k so all the upcoming Skylake devices could use target display mode with thunderbolt 3. What do you think?
If you can use the new Iris Pro to power a 5K monitor through a single cable, and there are machines in the current Mac line up that supports it, it also makes sense for a thunderbolt screen with 5K to be released. Otherwise its better to leave the display market for third parties. It such a small market now that laptops and phones dominate.