Hmmm... I do not know of ReWire opening any (slave) app and then loading the appropriate file one would have wanted *associated* with the file/session/song being opened in the host. If this is not true, then it is one step toward what I described.
Alternately, I am almost thinking it might simply be time for me to spend some of my free time getting into coding just to make a "master app" that will do what I described. The big issue I have is that I like to utilize certain aspects of Melodyne during the composing stage, and it seems to not take kindly to tempo and time sig changes without some work. Well, allowing them to be "fluid" during the composing stage- when I will change times, insert/delete measures, copy/paste, etc- is the issue I have. I thought Reaper had Elastique Pro licensed? If so, can we create something to actually utilize it?
As far as Sibelius... I have developed an irrational disgust with Avid (sorry, my keyboard does not have the symbol set to "spell" it properly
). Instead of upgrading my copy of Sibelius, I am considering buying Notion. Sibelius never sent the DVD that will install S5 on my W7x64 box, so up theirs.