I took a browse on the Haas website, they have an impressive online sales portal for a company that presumably does 99% of it's sales to company's, not consumers.
They definitely have a lot of add on stuff, and rigid tapping is on there. Whether they turn it on via the control or whether there is additional hardware needed, I do not know.
It's surprising that rigid tapping isn't standard though, because as we all know, even hobby grade machines can do it with the right hardware and software. Of course the Haas would decimate any hobby grade machine and you have to pay to play. I can understand it because of that.
I also checked out Syils, I built out sort of a dream machine, it came to $36k. Haha.