Perhaps you didn’t dig deeply enough on the forum to find Phil_Flood’s tutorial. Here’s a link: Using BB to play actual backing tracks - a short tutorial
There are quite a few BeatBuddy songs as backing tracks posted to this forum as well.
You can use the tutorial to create backing tracks of any length as long as they are no larger than 100Mb.
However, with the new BeatBuddy 2, your drum sets can theoretically be up to 450Mb. I say “theoretically” because it remains to be seen if this can be done in actual practice.