I thought there used to be a jazz trio swing trading fours real track, but I can't seem to find one now. If not, it would be nice for PGM to make one.

Do any of these hit the mark?

JAZFOURB.STY. Jazz Fours B - Trading 4s Var.
All MIDI. Quartet. Tempo=180 (100-300)
Instruments: M-Acoustic String Bass, M-Ac.Piano, M-Jazz Electric Guitar
M1 Standard Drum Kit
M33: Acoustic String Bass
M1: Acoustic Piano
M27: Jazz Electric Guitar
Memo: Jazz quartet (piano, bass, drums, jazz guitar). Similar to JazzFours.sty, the 'trading fours' order is: At A and B, 4 bars band then 4 bars drum solo. T=100-300

JAZFOURA.STY. Jazz Fours A - Trading 4s Var.
All MIDI. Quartet. Tempo=180 (100-300)
Instruments: M-Acoustic String Bass, M-Ac.Piano, M-Jazz Electric Guitar
M1 Standard Drum Kit
M33: Acoustic String Bass
M1: Acoustic Piano
M27: Jazz Electric Guitar
Memo: Similar to JazzFours.sty, this variation changes the 'trading' order. At A, regular jazz swing. At B, 4 bars drum solo, then 4 bars band. T=100-300


JAZFOURC.STY. Jazz Fours C - Trading 4s Var.
All MIDI. Quartet. Tempo=180 (100-300)
Instruments: M-Acoustic String Bass, M-Ac.Piano, M-Jazz Electric Guitar
M1 Standard Drum Kit
M33: Acoustic String Bass
M1: Acoustic Piano
M27: Jazz Electric Guitar
Memo: Jazz quartet (piano, bass, drums, jazz guitar). Similar to JazzFours.sty, the 'trading fours' order is: At A and B, 4 bars drum solo - 4 bars band. T=100-300


Krupa4s2.STY. Krupa 4s 2 - Alternate to KRUPA_4S.STY
All MIDI. Quintet. Tempo=210 (150-300)
Instruments: M-Acoustic String Bass, M-Ac.Piano, M-NylonGuitar, M-Vibes
M41 Brushes Kit
M33: Acoustic String Bass
M1: Acoustic Piano
M25: Nylon String Guitar
M12: Vibes
Memo: Alternate to KRUPA_4S.STY, 40s Jazz Swing - less busy drums in trading fours. 5 instruments: acoustic piano, acoustic guitar, acoustic bass brushes (sticks at B), vibes pad. T=210

Krupa_4s.STY. Krupa_4s - 40s Jazz Swing - trading four
All MIDI. Quintet. Tempo=210 (150-300)
Instruments: M-Acoustic String Bass, M-Ac.Piano, M-NylonGuitar, M-Vibes
M41 Brushes Kit
M33: Acoustic String Bass
M1: Acoustic Piano
M25: Nylon String Guitar
M12: Vibes
Memo: 40s Jazz Swing - drums trade fours with the soloist in the B - section. 5 instruments: acoustic piano, acoustic guitar, acoustic bass brushes (sticks at B), vibes pad. T=210

D*** I just posted a request for this.

Search for "Fours" in the Style Filter String and you'll quickly find several of the ones already listed.