Hi yotsuya,
I managed to get a real HD quality for the three missing scenes (arrival on Coruscant, Senate, Night on Theed) and it will be - very soon - available in the “Despecialized” TPM I’m currently finishing.
BTW, there is a little more than those three scenes (ea : the night on Tatooine, digitally shot, was totally regraded for the DVD, with additional and missing frames).
I’m really tempted to do the 97 SE LD (PAL + NTSC, so that a PaNup could achieve a nearly-HD quality). The DC and the Faces are already available in very good quality, is there an interest in recapturing them?