So I looked at it, and the downside of this way is that if you have a non-numeric value, it will magically be turned into "0" in the playlist view (the value is still there, it's just displayed as a 0 in the table)... Perhaps this is acceptable -- It seems kind of weird that someone would put a string value in the track number anyway....

I'm fine with this. All my track numbers are numeric so it won't bother me. Anyone who puts text in track number fields deserves a smack anyway.