Excuse the stupid noobie question, but how do I add tracks when building a song in BIB so that I have a total of more than the seven available in the mixer window?

Well, I'm still a noob too. But I think that is the max for BiaB. If you have the Windows version then you also have Real Band where you can open your BiaB file and add as many (almost) as you want. Here are some videos http://www.pgmusic.com/videos.realband.htm See Beginner #3.

If you are using a Mac; I'm sorry. Maybe someone else can advise.

HTH

Use multiple sgu files, render tracks to audio, combine audio tracks in RealBand or daw of choice.

Click Here For more Information.

yeh, I've been saving multiple copies of a song with different instruments, then combining them in Pro Tools. I thought there might be another way.

There's no way to do it with BiaB.
Yes, you have to export and then use a DAW. Realband allows up to 48 tracks.

Create your chord chart in RB and skip using Biab. It can save you considerable time.

Will,
Use Realband, it's like a stepping stone between BiaB and ProTools.
You get many more tracks (48), you can still generate (with more flexibility and options than BiaB), record more audio, add more FX and enjoy more routing options (like auxiliary sends and subgroups) ..
Enjoy this step.

Yes, in my view, the best way forward is to use RealBand, There is some familiarity between the two programs which can really help.

And we never need to excuse ourselves to ask any question on this forum! OK?. Everyone learns from all of our shared experiences, me too.

Will, I have suggested that PGMusic open all 16 tracks to the user and let the user decide what to assign to them. For instance you could have 16 RTs, MIDI or a combination of both. You could assign 6 tracks for a MIDI guitar or more than one for either the melodist or soloist etc. You should put this on the wishlist. I know myself and others would +1 it, again!