It would be killer feature since there are no commercially manufactured compact mechanical keyboards with trackpoint on it — right now you can go with Unicomp EnduraPro (but it’s still full sized), or (if you’re lucky enough) you search ebay and wait for one of the rarest IBM M13 spacesaver version (not likely). There are also some modern keyboards like Tex Yoda — but still it’s not serially produced, people are waiting it for a long time, right now there are around 4000 requests on the massdrop — and all because of trackpoint.
Just to add one thing about the Unicomp pointing stick kit:
I’ve asked Unicomp before*, and they told me that it is not a strain-gauge-based TrackPoint like the ones on ThinkPads, but an actual mechanical joystick, and suggested me against purchasing their pointing-stick-equipped products.
So if I understand correctly, that pointing stick moves mechanically, and it feels very different from any TrackPoint and their clones (like the ones on Dell and HP business laptops).
*Full disclosure: the context was about purchasing a keyboard from them, before I joined here, and I was debating about the EnduraPro over the standard ones.