Kawai was one of the ones I was thinking of. I agree that one would expect them to do this, but as far as I can read into their claims, they don't. It's just a volume pedal. 
I run my DP using pianoteq (which some people seem to think is rubbish, but I strongly disagree) - it certainly emulates ALL elements of the piano. I refuse to use my DP's on board sound now because there is no sympathetic resonance.
Pianoteq modals it accurately (atleast close to). Depress a key (no pedal) soft enough that it doesnt sound, depress another key and you will hear the resonance in the strings of the first one.
EDIT:
I'm no expert, but I fail to see how a sampled piano can beat this.. every key would have to be sampled at different velocities and with every possible combination of every other key. No current PC could handle it, or store the amount of samples required.
They have a note in the features saying that they modal the tonal difference when the una corda pedal is depressed.