The reason spirit and jetblue don't have the TPIC requirement is for the exact reason you specified, 121 FO's looking for jobs. You're TT is very competitive (infact more than) however, while your multi is very decent for any instructor, and impressive when it comes to getting that first job, it's also around as much as a airline pilot flies in 4 months time.

If you'd like to get to spirit or Jetblue, my advice would be a year getting some 121 turbine experience as an SIC, and then put in your application, worst they'll say is no. Plus, you'll be looking at having 3100 hrs TT, plus 1000 hrs SIC-Turbine, if they don't bite, stick it out another year or two, upgrade, and leave whenever the time is right. With the time you have though, i'd be picky about where you go, in this current industry, you're very marketable, so don't settle for a lowball, or location that you don't want to be.

PS- Had a RAH guy jumpseating with us the other day, and i thought he said they have a ATL base for the 170, but i'm not 100% sure. Might be worth checking out.