Yeah I read that you need a good pc to be able to use 4k without lag. :< I don't know if they have tablets that don't need to be connected to a PC but I think if that's what you want, an iPad would probably be a better option.. Or upgrade your laptop and buy a smaller display that isn't 4k, and that would probably be almost the same price as an iPad pro anyway hahah.
I was hoping they'd have the bigger iPad pros this year but sadly the new ones really have not much upgrades from previous ones. A 12.9" is already quite big tho, but maybe a 16" would be nice just to carry around in the house while drawing. I don't think I'd buy a 16" and carry it outside. XD
I checked it out, they have one, a 22" Kamvas Studio but I in the end I actually bought a new laptop. A Black Friday deal. Now I'll wait a bit longer and see what I'll do. I'm sure I'd also miss the touchscreen although that is a habit that can be changed. Well, for now, I'm looking forward to my new laptop while continuing on my iPad Pro.