Unless Microsoft was to pay for the entire development process, it definitely wouldn't go to the 360. Only way the 360 gets a lick of Shenmue is to release Shenmue 2 on the Xbox Originals (didn't they discontinue that?) or have 1&2 together as XBLA titles.
On the PS3, it definitely would NOT get a Shenmue 3 unless Sega reused assets from the Yakuza titles. Seeing as to how it succeed in Japan, but fail in the West (like the last couple Yakuza games) I doubt they would spend the money to do that. PS3 is the most expensive to develop for, and creating an overworld with that Shenmue scope would be beyond costly.
I doubt multiplatform would recoup costs either, but maybe if the budget was truly handled perfectly.
Now, last but not least Wii. Now, unless Nintendo has gone crazy, and really wants to dish out the goods by snatching exclusivity of this title as well (overseeing development, publishing assistance) they wouldn't get it on the Wii either. It is the cheapest to develop for, but they would have to see how the market reacts to a "Shenmue Collection" first (why this hasn't happened on any console, I don't know). It would be the safest bet in case it fails, but somehow seems like the least likely to happen.
Overall, I think the first second of S3 development would be with the mindset that this is releasing for the next generation of consoles. But if it were to turn up, it would be anyone's game. For the sake of argument, I'd say:
%40 chance multiplatform
30% chance 360 exclusive
20% chance Wii exclusive
10% chance PS3 exclusive
Leatherhat on July 6th, 2012 3pm. Vita sales:"3 mil for COD 2 mil for AC. Maybe more. " thehusbo on July 6th, 2012 5pm. Vita sales:"5 mil for COD 2.2 mil for AC."