Oh, I posted about that and then totally forgot about it. 
When you create a new post, go to the gear icon in the menu, and you will see an option in the submenu “Build a poll”. You only have 5 minutes to edit it after you post, so make sure you have the right options when posting.
I did a search for a matte 2160x3840 14.0" screen and I found one model by BOE. When I do a web search, I can find no devices using this kind of screen, so BOE can make it, but it is highly unlikely that BOE is currently making it. Purism is talking about a couple thousand units per year, and I doubt BOE will do a production run for a reasonable price per unit. In other words, you can forget about it.
Then I did a search for matte 1440x2560 14" displays and found there are 7 models made by 2 companies (LG Display and AUO). If one of the big laptop companies (like Lenovo) is using this part, Purism might actually be able to get it for a reasonable price, but you are still talking about double or triple the price of a matte 1080x1920 14" screen, because there are 50 models available for that part from nearly every major screen manufacturer.