I still have a problem with build 1493 though it appears to be a different problem. I am synching a collection of ab 1600 tunes and I tunes crashes after about 600 tunes - though it appears to vary. I am using the debug build and it generates an error report but it appears to die completely when I hit the submit button.
The error message I get is:
I've saved a copy of the itunesCDB file at https://dl.dropbox.com/u/80428042/iTunesCDB_MM
but it seems very small.
There is also a copy of a dbgview log at https://dl.dropbox.com/u/80428042/MM_error.log
if that helps.
This also appears to be a problem with build 1492 but not with build 1491 which had the separate problem of iTunes no longer recognising my 3rd gen ipod touch.