Here's a simple workaround for those who don't like TinySBS's scan-the-whole-disk behavior, but don't want to get into the Perl hacking that John S outlines: make the rest of the drive hidden to TinySBS.

As TinySBS is Linux, that means putting a "dot" at the beginning of the names of relevant folders. For example, if your USB drive has the following top-level directories

documents
music
photos
videos

change them to
.documents
music
.photos
.videos

and TinySBS will see only "music". I just tested it and it worked perfectly. WinXP wouldn't let me prepend the dots, so I had to do that in Linux. Note that the hidden folders are still visible outside of SBS, so you can still use them as before.