I have one I built from the Roland S-series sample library. Since the library is free now I guess it would be OK to share.
I'll try to get to posting it if I can find it; it's been a while since I used soundfonts, but I think it's still on one system here.
Howard, who was a long time member here (and is sorely missed) really liked it. I'll see if I can find it for you to try. It has some pretty cool velocity switching in it.acoustic guitars.
Edit-
Here it is. It is what it is; newer synths have much better acoustic guitars. This was made back when soundfonts were more common so it's a bit dated. Above the acoustic guitar range are some finger slide noises (for effect if done right), below the range are a couple other incidental noises, and the velocity switches between light and hard picking.
http://audiomastering-online.com/stuff/nlngtr3.SF2Some liked it, some didn't. If you learn to 'play' it, it can be usable. If you put it on a prerecorded midi track, who knows?
When I compare it to the acoustics available from modern synths I am amazed at the progress.