1) Upgradable officially, RAM only. Unofficially, basically everything apart from the graphics cards (so that's CPUs, RAM, SSD). The latter two are easy to do.
2) We'll likely see a 5K monitor from Apple once official support arrives for such a resolution (DisplayPort), however right now that doesn't exist (and the 5K iMac is the only 5K display you can get).
OK, How far off do you think that new apple monitor is? also is it then usable with the present Mac Pro? what I'm thinking is getting the Mac Pro now and using my current monitor and then buy the new one when it comes out.
I've got a few things lined up from the start of the year and that's why I want to get settled now and not swap everything in the middle of projects etc.
Fallen God: Mainly going to be used for Lightroom/Photoshop but also Premiere Pro/After Effects just not sure how much of the later 2 and they're the ones that need the power usually.