Do you think Apple will release a 21.5 cinema display?

I'm looking to have a dual display of 21.5 inches set up at my office. Apple stopped making that size a long time ago. I know that its almost for sure that they will update their 27 inches model with 4k and the new design but what about the 21.5? Do you that size will be brought back and updated as well? It's been forever since they updated the cinema displays, and the leaks of the 4k codes in the OS makes it seem like its going to be this year.

I'm going to be connecting that display to my Retina Macbook Pro which in the tech specs of it states that it can support up 2 external displays with a resolution of 2560-1600. Since 4k is much higher than that, will I not be able to utilize the 4k? will the monitor work for me at all? And say I get one cinema display once its out with the higher resolution, will I be able to have 4k since its 1 monitor as opposed to 2? So perhaps 2560-1600*2?

Given that I will be using my 13" Macbook Pro, do think I'm better off stick with a non-Apple display and perhaps buy it now? or do you think I should wait and get something from Apple?