Since Tamron released the full frame 150-500 in X-mount, I think there is a real chance they'd do the same for the 70-180mm. I hope they do, it is an outstanding lens.
The first generation, 70-180 f2.8, Nikon rebranded it to a Nikkor lens. Then Tamron upgraded the optics and added OIS without adding much size/weight in the G2. It looks like a smashing lens. I am not only hoping that it is ported over to the X mount as a replacement of the 50-140 f2.8 which is an aged lens design, but also to the Z mount where it would one would only give up 20 mm for a lens that is half the size and half the cost of the Z 70-200. I have the Tamron Z 150-600 which is a really nice lens on the Z mount.
Tamron has been making some really nice high quality lenses zoom lenses of late. The new Z mount 28-75 G2 is a top notch lens and after I recently picked it up spends most of its time on my Z8. The 17-70 X mount seems like a top of the line option for a mid range zoom for X mount.