Realtracks set 15 is Mainstream Jazz Soloing
http://www.pgmusic.com/realtracks15.htm

Accordian is on RealTracks sets 106, 119, 120

You're likely thinking of MIDI style set #15, which has styles like C_CAJUN
http://64.40.109.32/audio/allstyledemos/C_CAJUN.wma


Have Fun!
Peter Gannon
PG Music Inc.