Applied Acoustic Systems (AAS) makes the very nice "Lounge Lizard" electric-piano virtual instrument (fully modelled).   They also have a percussion synth (also modelled):

https://www.applied-acoustics.com/chromaphone-2/

This looks like a "black Friday" sale price.

The problem is:

. . . What can you use to play it ?

Any timpani player can get subtleties out of their drum that don't flow, easily, through a MIDI data stream.  The tone depends on where you hit the drum, _how_ you hit the drum (how long the mallet stays on the head, _which you can control_ with your fingers), how you "damp" the drum (with your other hand), and so on.

IMHO, a timpani "synth" will have the same problem as guitar "synths":

. . . The acoustic instrument responds to the player's input in ways that can be modelled, but that are difficult to gather data for.

Next time in a large music store, ask to play on a Roland "HandSonic" or a Korg "WaveDrum" (rather rare).  That will give you a sense of what the problem is.

.          Charles

PS -- I have Lounge Lizard, and it's fun to play.  i don't know if it's "realistic" (I've never played a real Rhodes EP), but it sounds very good.   I haven't tried "Chromaphone".

and since we already have bells, carillons, xylophones, vibes, celestes, and steelpans, maybe we could also get woodblocks, tablas, bongos, congas, etc and rename the program to "Percussionteq"...

seriously though, in keeping with the spirit of Pianoteq, i can think of a host of other historic 18th & 19th century pianos ('admittedly biased here) that would be incredibly valuable to have implemented from the standpoint of both performance as well as historic conservation before such, undoubtedly interesting, fancies as timpani were to be considered...

'just say'n 

I agree. As nice as percussion instruments would be, they would take time away from the pianos...

seriously though, in keeping with the spirit of Pianoteq, i can think of a host of other historic 18th & 19th century pianos ('admittedly biased here) that would be incredibly valuable to have implemented from the standpoint of both performance as well as historic conservation before such, undoubtedly interesting, fancies as timpani were to be considered...

'just say'n 

I just have to replace a percussionist this WE and indeed playing timpani rolls is not easy... except if you use a sample of... rolls ! My Juno DS (with "orchestral" expansion) just does this. I could not play such rolls so fast with my fingers: there is no comparable "rebound" on a keyboard. This being said, why not...?

An idea could be double strikes on single key, one on note on and the second one on the release. Then it is much easier to play fast rolls.