While I was instructing out of S67, I used to have some students that worked the ramp for QX in BOI, but not sure if they are still there. I also used to know the station manager for Southwest in BOI, but I believe he moved down to PHX. I still have the contact info for the station manager for SkyWest in BOI. Most airlines will advertise for rampers on their company web site.
I'm back living in BOI for the time being. Let me know if I can be of any assistance, I have a few cntacts around this area.