Yes to what Jim said.
I requested MultiTrack Drums for BB/RB, in BB you can have a MultiTrack Drum Mixer window to get the drums how you like and in RB they just split into separate tracks.
There are some multitrack drum here http://www.realband.org/drums.html you can just drag n drop the section/fills into RB. You could do the same as Jim said with loop sections/chords. You could use Audacity or REAPER if you have it to make them up.

RealTracks are basically the same idea as UserTracks (only bug at the moment stereo tracks generate in mono (let alone 5 channels) but should be fixed in next version), Reatracks just have a lot more recorded time than most currently available UserTracks as PG only supplied basic UT templates, but there's nothing stopping anyone from making longer templates.
If you open a current rhythm RealtTrack wma/wav one at a time in the Audio Chord Wizard (ACW) you can create some templates from these. There's lots of playing, lots of keys n chords, this is what makes them good. You CAN'T have a good UT with a 1 minute template, even the 10,20,30 minute, there's way more time in RealTrack recordings that's all.