This company makes trackpoint mechanical keyboards, but they're main schtick is reviving the Model M: https://www.pckeyboard.com/page/category/UKBD

I'm working on a modification for a different product with a trackball, but learned about the trackpoint as well. The patent recently expired and besides that, it's ~$10-20 to buy a trackpoint component and you could hack it into a keyboard if you had the time and willingness.