I use The Jazz Piano files from PG Music (www.pgmusic.com). You will need to buy the midi files but they are very well done. Folks like Renee Rosnes have recorded direct to midi to make for some pretty masterful takes.
I love using the files to learn and to \"road test\" my libraries as well.
A pretty wide selection of jazz styles and artists exist.
Hope this helps your search - sorry it is not a \"freebie\" site.