If you asked me, several months would be an exaggeration, but we do have some weeks of waiting ahead of us.
Let me explain; First, we need to have all the mods updated to 1.3. Updating all the mods usually takes the modders a lot of time, but this time, it will be even worse, due to the SSP/SMP merge that completely fucks with all the SSP mods. Then, all the mods have to get their updated version ported to Forge, and not all the modders do this themselves. Finally, depending on how exactly the merge works, most or all the mods might need to be ported to Buckit as well, which is a tremendous pain in the arse.
Add to all this crap the time it'll take for the Technic team itself to get the mod pack to work nicely and...
You got a fuckton of time.
Questions? :D