Anybody know of a tangent piano vst or kontakt instrument?

Tangent piano is a peculiar sound. Sounds like 50% piano and 50% harpsichord.

Example- http://www.youtube.com/watch?v=CoKj-l3DrPI

 

I don't know the specific of the construction of this particular piano but listening to the sound it appears to be very close to early fortepianos. I would suggest you take a look at this Pianoteq free add-ons from the Kivir collection: Schantz, Schmidt, Walter, Clavichord (this is in particular because it is an instrument that actually uses tangents, features piano dynamics and was modelled after one that C.E.Bach possessed). I would also check the Dohnal and the Broadwood from the Kremsegg collection 1-2 (you have to buy these instrument packs along with PT however because they're not free).
As for Kontakt libraries, the ones I am aware of belongs all to Realsamples. So you might want to check their pianos in particular the Early pianoforte because all the rest are harpsichords and later pianos.