There's a lot going on out there lately with the Tridentine Mass. The French are upset while it is suggested that the whole indult Motu Proprio is the project of the Colombian cardinal. The Apostolic Exhortation with the results from the Synod still waits to see the light of day. Curial appointments have been made and much hay has been made in discussing them.
That's only the half of it. But to what does it all point?
Other more informed sources believe that the indult Motu Proprio is just waiting for the right moment to come out once Benedict gets everything set up the way he wants. Bishops must be included, parameters for usage must be delineated, etc. At this juncture, I think that the whole rationale for this move with be completely explored in the Apostolic Exhortation from the Synod with the purely legislative actions coming in the Motu Proprio. The actual date of the signing and/or promulgation of either document remains to be seen. The possible contents are my own pure bits of speculation, but it would make sense to separate the pastoral arguments from the purely canonical provisions for the use of the Tridentine Mass.
Over at Father Z, rumors of the signing date include any day from the 7th inclusive.