Along the same lines, I just picked up the
Cakewalk Dimension LE with Garritan Pocket Orchestra for $5.
This is
not the same as the GPO (Garritan Personal Orchestra)! It's similar to the Miroslav library, in that it's a scaled-down version of the full library. I also suspect it's a slightly older version of the library.
Another bonus is that the instruments also come as
.sfz (SoundFont) files. I've already got the full GPO, but the SoundFont files will come in handy for my son, who likes to "re-arrange" MIDI files.

It wouldn't work
within BiaB, but if you export your MIDI tracks to a multitrack the supports multiple VSTis, it would be a good match.
I had a bit of trouble with the download - the installer said the file was corrupted. After a couple of days, I got a response from technical support and a link to a good download.