The last time around (2010) SD announced that interviews/hiring would begin, via memo, pretty far in advance of guys actually showing up to class. I can't remember the exact time frame because it was 3 years ago, but we will all have plenty of notice when the start spooling up. I'm remembering 3-4 months, but that could be off by a bit.
I was in for CQ last week and was hearing the same thing - classes running from Jan-May (~50/month). That means they'd have to start interviewing by roughly September I'd think to get thinks going in. That coincides with the 717 and 737-900 deliveries hitting full stride also, so the rumor seems to jive.
It really will be nice when the dam finally breaks and we get some movement. Someone on here recently raised the point that once guys start advancing it requires even more staffing to fly the schedule because a certain % of pilots are in training at any given time. The kind of vicious cycle we all want
Hopefully we'll get some good news here in the next few months.