If the nMP gets updated in the next 6 months does anybody think we will get new GPUs? D400, D600 and D800 maybe.
Are new FirePro cards due to be released anytime soon?
Already released, 7100, 8100, 9100.
I'd be surprised if 3rd party manufactures went to the effort to create a custom part for the Mac Pro.
Mac cards in the past were essentially standard PC cards by comparison. Add a bit of compatibility and jack up the price. Thanks to the hard work of those around here and elsewhere there are lots of unofficial options. Don't think this will happen with new Mac Pro.
Will be more interesting to me if we see any kind of official BTO option from Nvidia or an aftermarket option with this generation. The 7100-9100 seem fairly straight-forward for upgrades to the current versions.
It depends. Maxwell looks like a good candidate for the Mac Pro, but I don't know if Apple could ship a Mac Pro with a bridge that works for both Crossfire or SLI. At the end of the day, it's just pins, so it may not matter, but if the pin count is too small it could be an issue.
I don't think Apple will want to change the pin count for the card attachments between revisions, especially if they want to do an upgrade program for older Mac Pros (which I put at 50/50 chances right now.)
I also don't think Apple would add an Nvidia card just to appease CUDA users. Apple doesn't care about CUDA, and if it came to it, I'd see them suggesting using an Nvidia accelerator over Thunderbolt or something.