I realize this is an old post, but in case you are still interested, I did actually make an Excel spreadsheet of all the instances of various leitmotifs and themes (that I could detect!) a while back. It lists the track and time index where each theme is heard (using the SE releases for the OT, the UE for TPM, and the OSTs for II and III), or the time index in the movie for material that hasn’t been officially released on CD. If it’s of any interest, you can find it here: http://hep.bu.edu/~slinden/Themes_OST.xls