Sperfly--
Your career progression is very impressive so far... nice job. IMHO, going straight to a major with your turbine-time experience being turbo-prop only is possible, but you might have to compensate by having more total time than if you had 121 or jet experience. My class at SW had some guys with turbo-prop only turbine time, including me. The part that might work against (or at least not for) you is that almost all airlines work at least a two-person crew, and I think if they are going to hire a guy with prop-jet experience only, they would like to see a good amount of crew experience. If you are going to stay with your company, I'd see about flying the BE-350 (I think it requires a compliment of two). If you are going to leave and go to a regional, I'd recommend waiting until you have 1300 PIC turbine so you will have the required experience for FedEx and SW, as long as you are earning hours at your current job at a pretty good rate.
Good luck!
V1 ROT8