No.

A drum track of an individual sound doesn't really make sense - because a loop will do the job a lot easier.

I made a (user) Drum Track of HandClaps...and offered it up to anyone who wanted it... but, then I realized that creating a Loop of the same thing was a whole lot easier - for me AND the user (whoever wanted to download it).

The cowbell loop works. Why would you need a Drum track for it? Plus, you can add the loop in any track - in addition to a RealDrum. If the cowbell were a RealDrum track, you could not have any other drums (in BIAB). Same with the tambourine.

It is really easy to add your own loops...from anything you've got - tambourines, cowbells, handclaps, etc... creating a DrumTrack is a lot more work...