The only drum kit, where I could find brushes, has been the Studio Brush Kit, that has been included in the "Jam Pack 3: Rhythm Section Instruments".
I am not sure, if you still can get the Jam Packs at all. I purchased them initially on the installer DVDs, for the iLife version of GarageBand, then later again as a part of MainStage 3 for Logic and GarageBand 10, but click the "From the user guide" additional text, for some information on the Jam Pack 3 drum kits.
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Notes below C0 : Miscellaneous sounds relevant to the genre.
Notes C0 to C1 : Alternate drum kit sounds.
Notes C1 to B2 : Standard drum kit sounds, including kick drum, snare, hi-hats, ride
cymbals, crash cymbals, and toms.
Notes C3 to A♯3 : Basic Latin percussion, including bongo, congas, timbales and agogo.
Notes B3 to D♯5 : More Latin and other exotic percussion, including triangle, wood block, claves, guiro, and cuica.
Notes above D♯5 : Sound effects and other miscellaneous sounds.