Where is it stipulated that a transfer of regulatory duties covering flight crew licencing, from national authorities to EASA, will effectively take place on a specified date in the near future?
It isn't. EASA committees are currently transposing Joint Aviation Requirements into an new EU Regulation that will amend 1592/2002 to include licensing. The annexes to this regulation comprise the implementing rules that potentially do the damage. The best guess by those in the know for this task to be completed, given the tortuous processes of European lawmaking, is late 2009 or early 2010. However, there is, as yet, no specified date for completion.
Where can I find the text of these new regulations under which flight crew licences will be issued from the aforementioned specified future date?
You can't, the proposed text will not be published until the NPA process commences, probably in March 2008. The discussions on here centre around leaks of the first draft of the document that may, or may not, bear some similarity to the NPA.
The fact that your contacts in France and Spain are unaware of the process is probably because either they are not represented on the committee(s) or their representatives do not keep them as well informed as do the UK's. For example, the UK CAA held a seminar for training organisations a few weeks ago during which the attendees were left in no doubt as to the seriousness of the threat to national licences and ratings or of the CAA's (or UK Government's) inability directly to affect the outcome.